A revision of the South American species of the cleptoparasitic bee genus Triepeolus Robertson, 1901 (Hymenoptera: Apidae)

. The cleptoparasitic bee genus Triepeolus Robertson, 1901 (Hymenoptera: Apidae) is revised for species occurring in South America. A total of nine species are con ﬁ rmed from the continent, of which T. tu berculifer Onuferko, Rightmyer & Roig-Alsina sp. nov. is newly described. Four new synonymies are proposed: T. aguilari Moure, 1955 syn. nov. and T. megadelphus Cockerell, 1914 syn. nov. under T. buchwaldi (Friese, 1908); T. bilineatus Cockerell, 1949 syn. nov. under T. ﬂ avipennis (Friese, 1916); and Epeolus merus Brèthes, 1909 syn. nov. under T. nemoralis (Holmberg, 1886). Males of T. alvarengai Moure, 1955 and T. rufotegularis (Ashmead, 1900) and females of T. atoconganus Moure, 1955 and T. cecilyae Packer, 2016 are described for the ﬁ rst time. Lectotypes are designated for the following (all originally described under Epeolus Latreille, 1802 but now recognized as Triepeolus ): E. buchwaldi , E. ﬂ avipennis , E. osiriformis Schrottky, 1910 and its junior synonym E. luteipes Friese, 1916, and E. rufotegularis . Diagnoses and complete descriptions/redescriptions are provided for all species, along with a fully illustrated dichotomous identi ﬁ cation key (with Portuguese and Spanish versions available as supplementary material) to distinguish them based on external morphological features. Additionally, known collection records and information about the ecology of the treated species are presented.


Introduction
Triepeolus Robertson, 1901 is a large genus of cleptoparasitic bees distributed in the Holarctic and Neotropical regions, with 151 species recognized as valid before the present study (Rightmyer 2006(Rightmyer , 2008;;Rightmyer et al. 2014;Packer 2016;Gibbs et al. 2017).It is the most species-rich genus in the tribe Epeolini (Rightmyer 2004(Rightmyer , 2008)), which includes seven other genera: Doeringiella Holmberg, 1886, Epeolus Latreille, 1802, Odyneropsis Schrottky, 1902, Pseudepeolus Holmberg, 1886, Rhinepeolus Moure, 1955, Rhogepeolus Moure, 1955, and Thalestria Smith, 1854.Although South America is the continent with the greatest generic richness of epeolines and the only one where all eight genera are represented (half of which occur nowhere else), the South American Triepeolus fauna is depauperate compared with that of North America-the center of diversity of the genus (Rightmyer 2004).Moure (1955) included a review of the South American species of Triepeolus, wherein three species were newly described.Rightmyer (2008) provided a key to the species of the genus in South America and the Caribbean; however, this treatment was incomplete for South American Triepeolus.Although the key excluded names deemed redundant by the author, they were not formally established as junior synonyms in the article.Additionally, the key included a newly identifi ed but undescribed South American species.The known South American species of Triepeolus are divided between two large and taxonomically diffi cult species groups (comprised of species resembling T. simplex Robertson, 1903 and T. verbesinae (Cockerell, 1897), respectively), both of which were excluded from Rightmyer's (2008) revision and intended to be the focus of a separate taxonomic study.Another new and previously unknown species of Triepeolus from South America (based on a single, male specimen from Chile) has since been described by Packer (2016), although not in the context of a taxonomic revision.
In the present study, the species of Triepeolus known to occur in South America are formally revised, with up-to-date taxon concepts presented for all species.Additionally, information on the ecology of the treated species (if available) and their ranges is presented.

Material and methods
Species were delineated based on discrete morphological features.A lack of DNA sequence data for species of Triepeolus represented in South America (other than two DNA barcodes available for T. fl avipennis (Friese, 1916) and one for T. rufotegularis (Ashmead, 1900)) precluded the use of an integrative systematics approach.Specimens from 23 entomological collections were studied (see Supp. fi le 1 for the complete list).The primary types of all species of Triepeolus known from South America and their junior synonyms were examined by at least one of the authors of this revision and imaged (see Supp. fi le 2) except for the holotype of Doeringiella nemoralis Holmberg, 1886 (orig. comb.), which has been destroyed.A few secondary type and non-type museum specimens were studied exclusively from images as noted in the 'Material examined' sections under the treated species.Oth erwise, the lists of vouchered material are based on specimens personally examined by TO, MR, GARM, and/or ARA.Observations based on images of live specimens submitted to iNaturalist (https://www.inaturalist.org/)are also presented but listed separately under 'Non-preserved material', as in Onuferko & Sheffi eld (2022).Identifi cations of all iNaturalist specimens cited here were made or verifi ed by TO.Specimens were observed under a standard dissecting microscope and measured using a calibrated ocular micrometer within the eyepiece.Images were taken (mostly by TO, GARM, and ARA at their respective institutions) using diff erent camera systems (with diff erent light settings) and focus-stacking software.Photographs of specimens deposited in the ZMB were taken previously by GARM during his stay in the museum in 2015 and 2016; for this publication, new photographs were taken and provided ONUFERKO T.M. et al., A revision of South American Triepeolus (Hymenoptera) by the ZMB digitization team and collections staff , respectively.Consequently, diff erences in the coloration of illustrated specimens may appear more pronounced than they are and should be interpreted cautiously.Images were minimally edited (to enhance brightness/contrast and adjust the color), resized, and cropped in PaintShop Pro (Jasc Software, Inc.), and labeled fi gure plates were compiled in Adobe Photoshop 2020 (Adobe Inc.).

European Journal of Taxonomy
The terminology for morphological features used here is largely consistent with that of Rightmyer (2008), which generally follows Michener (2007), but with some modifi cations as follows.As in Prentice (1998), 'frontal area', 'genal area', and 'vertexal area' are used instead of 'frons', 'gena', and 'vertex', respectively, since these parts of the head are not clearly delineated externally (see Mir Sharifi et al. 2019 for a recent example of the use of these terms in bee taxonomy).Herein, 'length' (except in reference to setae (hairs)) and 'width' do not refer to the longer and shorter sides of a particular shape (as in geometry) but rather measurements made along the longitudinal and lateral axial planes, respectively.Terms introduced for Triepeolus by Rightmyer (2008) and subsequently used in taxonomic studies of other cleptoparasitic bees (e.g., Onuferko 2019) are also explained here for clarity.In most species of Triepeolus, the mesoscutum has a pair of subparallel lines of pale tomentum originating in its anterior half, which are termed 'paramedian bands'.The region of dark, short, appressed setae fl anked or surrounded by bands of pale setae on the fi rst metasomal tergum is called the 'discal patch'.The fi rst metasomal tergum has a 'basal band' of pale tomentum, which may be separated medially int o a pair of anterolateral patches, and at least the second to fourth metasomal terga have 'apical transverse bands' of pale tomentum, which may be narrowed or interrupted medially.The mesoscutellum in Triepeolus has a pair of weak to strong rounded convexities and is thus described as 'bigibbous' to varying degrees, following Moure (1955).The name-bearing types (holotypes and lectotypes) of the treated species served as the basis for the descriptions/redescriptions, with references to other examined specimens added as needed to fi ll in information gaps.In the case of T. nemoralis, the holotype of E. merus Brèthes, 1909 (herein regarded as a junior synonym of T. nemoralis) served as the basis for the redescription, since the type of the former has been lost.Since Triepeolus is largely sexually monomorphic, a single description that applies to both sexes is provided for each species, with female-and male-specifi c features described under separate headings (as in Rightmyer 2008).Exact measurements of size (in mm) are given for each primary type that bears the accepted name for the species in question (except in the case of T. nemoralis as described above).Measurements of anatomical features were taken at their longest and/or widest extents, except ITW, which represents the shortest distance between the tegulae of a specimen.Body length was measured from the apex of protrusion of the supraclypeal area to the last visible tergum or sternum and does not include the terminalia, which are extended in some specimens.

Abbreviated
A morphological diagnosis is provided to identify Triepeolus among all other bee genera in South America.Separate diagnoses are also provided for each of the treated species.Additionally, a single fully illustrated dichotomous identifi cation key is presented to enable the identifi cation of both sexes European Journal of Taxonomy 931: 1-50 (2024) of the species of Triepeolus occurring in South America.Since Portuguese and Spanish are by far the most widely spoken languages in South America, versions of the key in both languages are presented in Supp.fi le 3.
Species distribution maps were produced in RStudio (ver.2022.07.0+548) based on known locality records, with the GPS coordinates associated with each observation taken either directly from the collection or image labels or, if not known, approximated from the named locality.The function 'getData' in the package raster (Hijmans 2022) installed in R ver.4.2.1 (R Core Team 2022) was used to download spatial data for the Global Administrative Boundaries (source = https://gadm.org/)used to construct projected maps onto which the occurrence records were plotted.The Robinson projection was selected for the maps and specifi ed using the function 'CRS' in the package maptools (Bivand & Lewin-Koh 2022) installed in R.
Available information on host and fl oral records was collated for the treated species.The World Flora Online (WFO) (http://www.worldfloraonline.org/)was consulted to ensure that the plant names presented herein are up to date.Although no single anatomical feature is diagnostic for Triepeolus, several features in combination separate the genus from all others in South America as follows.The front coxae are quadrate (as opposed to somewhat triangular), with the trochanters widely separated at their bases, and the axillae are produced to lobes or spines and thus do not continue the contour of the mesoscutellum (as in all Epeolini); the mandibles are simple; the scapes are normal (i.e., not fl attened, dramatically swollen, or each forming a laterally directed subbasal angle); the eyes are convergent below; the mesoscutum (except sometimes in T. nemoralis) and T1-T4 in all South American (and most other) species of Triepeolus have welldefi ned bands of pale (white/off -white to yellow) tomentum; the mesoscutellum does not have a median longitudinal strip of pale, short, appressed setae and is to some degree bigibbous but not denticulate or tuberculate; and the fore wings of all South American (and most other) species of Triepeolus each have three submarginal cells.In the species of Triepeolus occurring in South America (as in some but not all congeners elsewhere), the pseudopygidial area of the female is known to be either triangular (with the apical margin of T5 concave) or distinctly circular (with the apical margin of T5 broadly convex).

Distribution in South America
Triepeolus is found throughout most of South America but is notably absent from much of Chile and not known to occur in southern Patagonia.The genus is expected to occur in all 12 of the continent's countries as well as French Guiana but has not yet been confi rmed from the latter, Suriname, or Uruguay (see Fig. 1).(Friese, 1908).D. T. cecilyae Packer, 2016.E. T. fl avipennis (Friese, 1916).F. T. nemoralis (Holmberg, 1886).G. T. osiriformis (Schrottky, 1910).H. T. rufotegularis (Ashmead, 1900).I.

Diagnosis
The following morphological features in combination tell T. alvarengai apart from all other South American Triepeolus: the (medially narrowed or interrupted) T1 basal band is arched, continuous with (and indistinguishable from) the lateral longitudinal bands, and mesally concave on each side, such that the discal patch is semicircular (Figs 2B,3A); the mesoscutum has well-defi ned paramedian bands (Figs 2B, 3A); and T2-T4 have complete apical transverse bands of yellow tomentum (Figs 2B,3A).Specimens in which T1 has only a basal band or pair of anterolateral patches of pale tomentum (as in Fig. 2B) (as opposed to both basal and apical transverse bands, as in Fig. 3A) may be confused with T. nemoralis, but in T. nemoralis the mesoscutum has a large anteromedial ovate patch of yellow tomentum, which may be sparser medially such that the patch is suggestive of ill-defi ned paramedian bands.Males of T. alvarengai without an apical transverse band on T1 also closely resemble those of T. fl avipennis, but in T. fl avipennis the pair of anterolateral patches of pale tomentum on T1 are mesally convex, such that the discal patch forms a trapezoid or triangle with concave anterolateral sides.Females of T. alvarengai and T. fl avipennis are more readily distinguished by the pseudopygidial area, which in the former is triangular, with the apical margin of T5 concave, and in the latter is distinctly circular, with the apical margin of T5 broadly convex.

Etymology
The specifi c epithet (declined in the genitive case) honors L.C. Alvarenga, who collected the holotype (Moure 1955).

Both sexes I
. Dark brown to black except as follows.Mandible with middle portion reddish brown.Antenna (except for orange along outer and apical margins of F1 and orange spot basally on F2) dark brown in holotype; scape orange in part and pedicel and F1 extensively orange in some non-type specimens.Tegula dark brown in holotype; orange in some non-type specimens.Fore wing membrane subhyaline, apically dusky.Hind wing membrane dusky subhyaline to hyaline.Legs dark brown in holotype; trochanters to tarsi extensively orange in some non-type specimens.Pygidial plate reddish brown.European Journal of Taxonomy 931: 1-50 (2024) P .Face with tomentum densest around antennal socket.Tomentum slightly sparser on clypeus; upper paraocular and frontal areas and vertexal area mostly exposed.Pronotal collar with tomentum uniformly bright yellow.Mesoscutum with well-defi ned paramedian band of bright yellow tomentum, well separated from anterior margin; pale tomentum otherwise mostly restricted to lateral and posterior margins.Mesopleuron with off -white to pale-yellow, appressed, branched setae; densely setose just below scrobal groove (upper half otherwise sparsely setose); ventrolateral half nearly bare, except along margins.Metanotum with tomentum uninterrupted, pale yellow laterally and partially dark brown/gray and partially pale yellow medially (uniformly pale yellow in some non-type specimens).Propodeal triangle mostly glabrous, with (pale) setae restricted to small lateral patches.T1 with basal transverse band of bright yellow tomentum separated medially into pair of anterolateral patches, continuous with (and indistinguishable from) lateral longitudinal band, forming arch around semicircular discal patch; anterolateral patch with short, medially directed posterolateral extension in holotype; with medially interrupted apical transverse band in some non-type specimens.T2-T4 with complete apical transverse bands of bright yellow-orange tomentum without well-defi ned anterolateral extensions, although T2-T4 with faint lateral longitudinal bands of diff use off -white setae.S2-S3 with apical transverse bands of white tomentum.

S
. Labrum with pair of small subapical denticles.Pronotal collar short (medial length ~ ½ MOD).Mesoscutellum moderately bigibbous.Axilla extending beyond midlength of mesoscutellum but not as far back as its posterior margin; tip distinctly pointed and hooked (i.e., concave along medial margin), but mesally unattached to mesoscutellum for less than ⅖ medial length of axilla; lateral margin somewhat sinuate.

Female
T5 with concave apical margin and large patch of pale-yellow tomentum on each side lateral to pseudopygidial area.Pseudopygidial area with underlying integument dark brown in holotype (extensively orange in some non-type specimens), forming rounded triangle with concave sides, with brown spinelike setae laterally.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 straight in lateral view, with apical fi mbria of coppery bristle-like setae; S5 otherwise covered in off -white tomentum.

Host records
Unknown.

Floral records
Unknown.

Remarks
Triepeolus alvarengai exhibits unusual but continuous variation in the patterns of pale pubescence on T1, which may have only a medially interrupted basal band with a short, medially directed posterolateral extension on each side or both basal and apical transverse bands, with the latter varying in the extent to which it is separated medially.The description of the male of T. alvarengai is published here for the fi rst time.Moure, 1955 Figs 1B, 4A, 5 Triepeolus atoconganus Moure, 1955: 128 (♂).
Triepeolus atoconganus and T. cecilyae are the only South American species in the genus with long (≥ ½ MOD), erect/suberect setae on the upper face and much of the mesosoma, but in T. cecilyae these are longer for the most part (with many exceeding 1 MOD in length) and more abundant, covering much of both the upper and ventrolateral halves of the mesopleura.Additionally, in T. cecilyae at least the T3-T4 apical transverse bands of the female and T1-T4 apical transverse bands of the male are narrowed or narrowly interrupted medially.

Etymology
The specifi c epithet refers to the type locality-Atocongo (near Lima), Peru.The Latin adjectival suffi x '-anus' means 'of' or 'pertaining to'.

I
. Dark brown to black except as follows.Mandible with basal two-thirds, pronotal lobe, tegula, coxae to some extent, trochanters to tibiae (excluding brown meso-and metatibial spurs) partially to entirely, and tarsi entirely orange.Antenna entirely dark brown in lectotype; scape, pedicel, and F1 to some extent orange in multiple non-type specimens.Fore wing membrane dusky subhyaline throughout, slightly darker beyond venation.Hind wing membrane dusky subhyaline to hyaline.Pygidial plate to some extent reddish brown in lectotype and some non-type specimens.

P
. Face with tomentum densest around antennal socket.Tomentum slightly sparser on clypeus; upper paraocular and frontal areas and vertexal area mostly exposed.Labrum, clypeus, face around antennal socket, genal and vertexal areas, most of pronotum (including pronotal collar), mesoscutum (at least anterolaterally), and upper half of mesopleuron with off -white to dark brown/gray, erect, minutely ONUFERKO T.M. et al., A revision of South American Triepeolus (Hymenoptera) branched setae (reaching more than ½ MOD in length).Mesoscutum with well-defi ned paramedian band of off -white to pale-yellow, erect, minutely branch ed setae (tapering slightly toward but not attaining anterior margin in lectotype; attaining anterior margin in some non-type specimens); with off -white to pale-yellow, appressed, branched setae mostly restricted to posterior margin.Mesopleuron with off -white to pale-yellow, appressed, branched setae around pronotal lobe; upper half densely setose; ventrolateral half sparsely setose.Mesopleuron with sparse, erect, simple setae (reaching about ½ MOD in length) in addition to appressed and erect/suberect, minutely branched setae.Metanotum with tomentum uninterrupted, pale yellow laterally and partially to entirely black medially.Propodeal triangle mostly glabrous, with (off -white to dark brown/gray) setae restricted to small lateral patches.Metasomal terga with bands of off -white to pale-yellow tomentum, those of T3-T6 stained dark brown/black in lectotype (presumably due to poor preservation).T1 with basal transverse band widely interrupted medially, arched, and continuous with (and indistinguishable from) lateral longitudinal band; apical transverse band separated into pair of rounded lobes medially; discal patch triangular (semicircular in some nontype specimens).T2-T4 with medially widely interrupted apical transverse bands, that of T2 with pair of basomedially convergent anterolateral extensions (described from non-type specimens).S2-S3 with apical transverse bands of white tomentum (reduced to posterolateral patches in lectotype and some non-type specimens).European Journal of Taxonomy 931: 1-50 (2024) S .Labrum, clypeus, mesoscutum, mesoscutellum, axilla, and mesopleuron with punctures more or less equally dense and nearly contiguous (most i < 1d).Vertexal area somewhat sparsely punctate (some i > 2d) anteriorly and around ocelli, otherwise densely (most i < 1d) rugosepunctate.Mesopleuron with punctures similar in size throughout.Discs of metasomal terga with punctures very fi ne, dense (i ≈ 1d), and evenly distributed; interspaces shining somewhat.

S
. Labrum with pair of small subapical denticles, each preceded by longitudinal carina.Pronotal collar short (medial length ~ ½ MOD).Mesoscutellum moderately bigibbous.Axilla extending little if at all beyond midlength of mesoscutellum; tip visible but somewhat blunt, mesally unattached to mesoscutellum for less than ⅓ medial length of axilla; lateral margin relatively straight.

Female
T5 with broadly convex apical margin and large patch of off -white tomentum on each side lateral to pseudopygidial area.Pseudopygidial area circular, with setae glossy, predominantly grayish brown, and sparser centrally; apical margin with row of dense, appressed and suberect coppery to silvery setae.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 mostly straight in lateral view (slightly downturned apically), covered in mostly brown tomentum and with apical fi mbria of brown bristle-like setae.

ONUFERKO T.M. et al., A revision of South American Triepeolus (Hymenoptera)
Male T5-T6 with medially interrupted apical transverse bands of off -white to pale-yellow tomentum (described from non-type specimens).Pygidial plate apically rounded and slightly downturned, with basal transverse ridge ill-defi ned and lateral margin somewhat sinuate.S4-S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved setae; brown and contrasting strongly with posterolateral patches of white tomentum of preceding sterna in lectotype; coppery to silvery and not contrasting strongly with bands of preceding sterna in some non-type specimens.

Distribution
Presently only known from western Peru and interandean valleys (Fig. 1B).

Host records
Unknown.

Floral records
Labels of examined voucher specimens indicate that this species has been collected from Encelia canescens Lam.(Asteraceae) and Nolana L.f. (Solanaceae).

Remarks
The description of the female of T. atoconganus is published here for the fi rst time.(Friese, 1908) Figs

Diagnosis
The following morphological features in combination tell T. buchwaldi apart from all other South American Triepeolus: the mesoscutum does not have long (≥ ½ MOD), erect setae (Fig. 4C); the T1 basal band is arched and continuous with (and indistinguishable from) the lateral longitudinal bands, such that the discal patch is semicircular or triangular (Fig. 6B); T1-T4 have medially interrupted bands of pale-yellow tomentum (Fig. 6B); and the T2 apical transverse bands have lobe-like anterolateral extensions (Fig. 6A-C).Triepeolus buchwaldi is very similar in overall appearance to T. atoconganus and T. cecilyae, but in the latter two species the dorsum of the mesosoma (at least anterolaterally) and mesopleura (at least in the upper half) have dense, long (≥ ½ MOD), erect/suberect, minutely branched setae.

I
. Dark brown to black except as follows.Mandible with apical third golden yellow (entirely dark brown/black in some non-type specimens).Mandible with basal two-thirds, scape and pedicel to some extent, F1 extensively, pronotal lobe, tegula, coxae to some extent, trochanters to tarsi (excluding brown meso-and metatibial spurs) partially to entirely, metasomal terga laterally, and metasomal sterna to some extent orange.Fore wing membrane subhyaline, apically dusky.Hind wing membrane dusky subhyaline to hyaline.Pygidial plate to some extent reddish brown.

P
. Face with tomentum densest around antennal socket.Tomentum slightly sparser on clypeus; upper par aocular and frontal areas and vertexal area mostly exposed.Pronotal collar with tomentum uniformly pale yellow.Mesoscutum with well-defi ned paramedian band of pale-yellow tomentum, tapering slightly toward and attaining anterior margin; pale tomentum otherwise mostly restricted to lateral and posterior margins.Mesopleuron with off -white, appressed, branched setae; upper half densely setose, except behind pronotal lobe, with setae slightly sparser on hypoepimeral area; ventrolateral half sparsely setose.Metanotum with tomentum uninterrupted, uniformly pale yellow.Propodeal triangle mostly glabrous, with (pale) setae restricted to small lateral patches.Metasomal terga with bands of offwhite to pale-yellow tomentum.T1 with basal transverse band widely interrupted medially, arched, and European Journal of Taxonomy 931: 1-50 (2024) continuous with (and indistinguishable from) lateral longitudinal band; apical transverse band separated into pair of rounded lobes medially; discal patch triangular (semicircular in some non-type specimens).T2-T4 with medially interrupted apical transverse bands, that of T2 with pair of basomedially convergent anterolateral extensions.S2-S3 with apical transverse bands of white tomentum.

S
. Labrum and clypeus with punctures equally dense (most i < 1d); interspaces well defi ned, shining.Vertexal area densely punctate (most i < 1d).Mesoscutum, mesoscutellum, and axilla with punctures more or less equally dense and nearly contiguous (most i < 1d).Mesopleuron with punctures in upper half not much denser (most i < 1d) than in ventrolateral half (most i ≤ 1d); interspaces shining; punctures similar in size throughout.Discs of metasomal terga with punctures very fi ne, dense (i ≈ 1d), and evenly distributed; interspaces shining somewhat.

S
. Labrum with pair of small subapical denticles, each preceded by discrete longitudinal ridge.Pronotal collar rather short (medial length ~ ⅔ MOD).Mesoscutellum moderately bigibbous.Axilla extending little if at all beyond midlength of mesoscutellum; tip visible but somewhat blunt, mesally unattached to mesoscutellum for less than ⅓ medial length of axilla; lateral margin relatively straight.

Female
T5 with broadly convex apical margin and large patch of off -white to pale-yellow tomentum on each side lateral to pseudopygidial area.Pseudopygidial area circular, with setae glossy, predominantly grayish brown, and sparser centrally; apical margin with row of dense, appressed and suberect coppery to silvery setae.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 straight in lateral view, covere d in brown tomentum and with apical fi mbria of brown bristle-like setae.

Male
T5-T6 with medially interrupted apical transverse bands of off -white to pale-yellow tomentum.Pygidial plate relatively fl at and apically rounded.S4-S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved, coppery to silvery setae, not contrasting strongly with bands of preceding sterna.

Distribution
Ecuador and Peru, west of the Andes (Fig. 1C).

Host records
One (female) specimen of T. buchwaldi at the AMNH (M.G.R. Database No. 2260) is pinned with a specimen identifi ed by C.D. Michener as Florilegus purpurascens Cockerell, 1914 (Hymenoptera: Apidae: Eucerini), both of which were apparently taken from the same nest 14 km E of Tembladera in Cajamarca, Peru.Rightmyer (2006) reported this species on Bidens L. (Asteraceae) and Gossypium hirsutum L. (Malvaceae).Images on iNaturalist show this species visiting Ludwigia L. (Onagraceae).The label of one examined voucher specimen says "soybean var.trial bloom".

Remarks
In his treatment of South American Triepeolus, Moure (1955) indicated that he was not familiar with T. megadelphus.Howeve r, Moure subsequently examined the holotype, in 1957-the year indicated on his determination label (Fig. S9F in Supp.fi le 2)-and identifi ed the specimen as T. buchwaldi but did not publish the synonymy.The authors of the present study agree with Moure's designation, as the ONUFERKO T.M. et al., A revision of South American Triepeolus (Hymenoptera) specimen does not exhibit any morphological features to suggest that it belongs to a separate species, so T. megadelphus is herein synonymized under T. buchwaldi.Moure (1955) described T. aguilari based on a male specimen from Lima, Peru, claiming it to be similar to T. ancoratus Cockerell, 1916 from the southwestern United States.The types of both species are markedly diff erent despite both belonging to the T. verbesinae species group, with the latter (USNM 534611) exhibiting a transversely oblong (as opposed to triangular) discal patch on T1 and complete (as opposed to medially interrupted) transverse bands on T1-T4.The metasomal tergal bands in T. buchwaldi are typically more widely interrupted medially in the female than male, and the patterns of pubescence exhibited by the holotype of T. aguilari do not diff er markedly from those exhibited by the studied male type of E. buchwaldi-in both specimens, the metasomal tergal bands are only narrowly interrupted medially.Hence, the authors of the present study do not consider these to be distinct species, and T. aguilari is herein synonymized under T. buchwaldi.
Since Friese (1908) did not explicitly designate a holotype, one of the two studied syntypes-the male, which bears a red label that says "Type"-is herein designated as the lectotype of E. buchwaldi.The female, which is from the type locality and was identifi ed as E. buchwaldi by Friese but is not labeled as a type, is recognized as a paralectotype.Moure & Melo (2007) tentatively synonymized Epeolus xanthurus Cockerell, 1917 with T. buchwaldi and erroneously indicated the AMNH as the repository for the holotype of the former (the specimen is actually deposited in the USNM).Epeolus xanthurus is now correctly placed in Epeolus as a junior synonym of E. luteipennis Friese, 1916(Onuferko 2019).Packer, 2016 Figs 1D, 4B, 7-9

Diagnosis
The following morphological features in combination tell T. cecilyae apart from all other South American Triepeolus: the frontal area, dorsum of the mesosoma, and both the upper and ventrolateral halves of the mesopleura have dense, long (clearly > ½ MOD), erect/suberect, minutely branched setae (Fig. 4B) and the T3-T4 apical transverse bands are narrowed or narrowly interrupted medially (Figs 7B,8).
Triepeolus cecilyae and T. atoconganus are the only South American species in the genus with long (≥ ½ MOD), erect/suberect setae on the upper face and much of the mesosoma, but in T. atoconganus these are shorter for the most part (with few exceeding 1 MOD in length) and less abundant, covering much of the upper but not ventrolateral halves of the mesopleura.Additionally, in T. atoconganus the T1-T4 transverse bands are all widely interrupted medially.

Etymology
The specifi c epithet (declined in the genitive case) honors Cecily Bradshaw, a friend of the taxonomic authority and advocate for (and supporter of) bee research (Packer 2016).

I
. Dark brown to black except as follows.Mandible with apical third golden yellow (entirely dark brown/black in some non-type specimens) and basal two-thirds reddish brown.Labrum with small orange spot basolaterally.F1 orange in part.F2 with orange spot basally in some nontype specimens.Pronotal lobe, tegula, anterior metasomal terga laterally, and S1 to some extent reddish brown.Fore wing membrane dusky subhyaline throughout except around third submarginal crossvein and second recurrent vein, where subhyaline.Hind wing membrane dusky subhyaline to hyaline.Coxae to some extent and trochanters to tarsi entirely reddish orange (meso-and metatibiae, including spurs, and metafemur to varying degrees dark brown/black in non-type specimens).

P
. Face with tomentum densest around antennal socket.Clypeus, upper paraocular and frontal areas, and vertexal area mostly exposed.Labrum, face around antennal socket, most of pronotum (including pronotal collar), and mesopleuron along posterior margin above base of mesocoxa (and just below pronotal lobe and scrobal groove in non-type specimens) with off -white, erect, minutely branched setae (clearly reaching more than ½ MOD in length).Clypeus, genal and vertexal areas, most of mesoscutum, mesoscutellum, axilla, most of mesopleuron, metapleuron, and propodeum laterally with dark brown/gray, erect, minutely branched setae (clearly reaching more than ½ MOD in length).Mesoscutum with well-defi ned paramedian band of pale-yellow, erect, minutely branched setae (tapering slightly toward but not attaining anterior margin in holotype; attaining anterior margin in some non-type specimens); with pale-yellow, appressed, branched setae restricted to posterior margin.Mesopleuron densely setose throughout, with off -white, appressed, branched setae around pronotal lobe.Metanotum with tomentum uninterrupted, dark brown/gray except for small patch of off -white tomentum laterally.Propodeal triangle mostly glabrous, with (dark brown/gray) setae restricted to small lateral patches.T1 with basal transverse band of off -white to pale-yellow tomentum widely interrupted medially, arched, and continuous with (and indistinguishable from) lateral longitudinal band; apical transverse band of pale-yellow tomentum separated into pair of rounded lobes medially; discal patch semicircular (triangular in some non-type specimens).T2-T4 with medially narrowed or narrowly interrupted apical transverse bands of pale-yellow tomentum, that of T2 with pair of faint lateral longitudinal bands of diff use pale-yellow setae in holotype (with pair of well-defi ned basomedially convergent anterolateral extensions in some non-type specimens).S2-S3 with apical transverse bands of white tomentum, that of S2 interrupted medially (complete but narrowed medially in one non-type specimen).

S
. Labrum with pair of small subapical denticles, each preceded by longitudinal carina.Pronotal collar rather short (medial length ~ ⅔ MOD).Mesoscutellum moderately bigibbous.Axilla not extending beyond midlength of mesoscutellum; tip visible but somewhat blunt, mesally unattached to mesoscutellum for less than ⅓ medial length of axilla; lateral margin relatively straight.

Female
T5 with broadly convex apical margin and large patch of pale-yellow tomentum on each side lateral to pseudopygidial area.Pseudopygidial area circular, with setae glossy, predominantly grayish brown, and sparser centrally; apical margin with row of dense, appressed and suberect coppery to silvery setae.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 slightly downturned apically, with apical fi mbria of brown bristle-like setae and dark brown tomentum laterally, posteriorly, and in apicomedial triangular area; S5 otherwise covered in off -white to pale brown tomentum.European Journal of Taxonomy 931: 1-50 (2024) curved setae; coppery to silvery laterally, brown and contrasting strongly with bands of preceding sterna medially.

Distribution
Arid regions of southern Peru and northern Chile (Fig. 1D).

Ecology Host records
Packer (2016) suggested that Mirnapis inca Urban, 1998 (Hymenoptera: Apidae: Eucerini) might be the host of T. cecilyae based on its size and occurrence in the area where the holotype of the latter was collected.

Floral records
This species has been collected from Grindelia tarapacana Phil.(Asteraceae).

Remarks
Triepeolus cecilyae was described from a single, male specimen collected in northern Chile (Packer 2016).Its status as a new species was based in part on morphological comparisons to four specimens from Peru (two females and two males, all from the same locality and collected within a two-day period) tentatively identifi ed by the author as T. atoconganus (L.Packer, personal communication, 2023).These specimens and the holotype of T. cecilyae were personally examined by TO, and all appear to be conspecifi c.One of the diagnostic features of T. cecilyae identifi ed by Packer (2016) is that the T3 apical transverse band is complete (as opposed to interrupted medially).Additionally, in T. cecilyae S3 was described as "uniformly covered in pale hairs".In the two male specimens from Peru, the bands on the metasomal terga and sterna were partly stained dark brown/black (presumably due to poor pre servation) when received and initially examined by TO.Their original coloration was restored by applying small pieces of tissue paper dampened with 70% ethanol to the dorsal and ventral surfaces of the metasoma for several minutes.This treatment revealed that the T3-T6 apical transverse bands are complete in one of the two males from Peru (Fig. 8B) and the T3-T4 bands are only narrowly interrupted medially in the other.Additionally, in both specimens the metasomal sterna, including S3, were revealed to be extensively covered in white tomentum, as in the holotype of T. cecilyae (Fig. 9).Although the T1-T4 apical transverse bands are all interrupted medially in the two females (Fig. 7B), they are more narrowly interrupted than in what is understood to be the female of T. atoconganus (Fig. 5B).Three additional specimens (two females and one male) have since been discovered (also in Peru but closer to the type locality in Chile), and in the two females some of the metasomal tergal bands are complete albeit narrowed medially whereas the rest are narrowly interrupted medially.Another feature of T. cecilyae originally considered to be diagnostic is that the legs are entirely reddish orange from the trochanters to tarsi, but among the now seven known non-type specimens from Peru there is continuous variation in the degree of dark brown/black coloration on the meso-and metatibiae and metafemora, which range from almost entirely reddish orange to mostly dark brown/black.
The eight known specimens are far more similar to one another morphologically than to any studied representatives (including the lectotype) of T. atoconganus, agreeing with the present diagnosis for T. cecilyae.Most notably, in these specimens the mesosoma is more extensively and obviously "hairy" than that of T. atoconganus and the T3-T4 apical transverse bands are at most only narrowly (as opposed to widely) interrupted medially.Further suggesting conspecifi city is that all known collection localities (in Chile and Peru) are in the Atacama Desert and outlying arid areas along the Pacifi c coast.Based on known records, adults of T. cecilyae are active in summer and autumn (January to May).
Given the discovery of these additional exemplars of T. cecilyae, a re-description of this species is warranted.The female of T. cecilyae is described here for the fi rst time.

Diagnosis
The following morphological features in combination tell T. fl avipennis apart from all other South American Triepeolus: T1 has a medially interrupted basal band or pair of anterolateral patches of pale tomentum, which on each side (or each of which) is mesally convex, such that the discal patch forms a trapezoid or triangle with concave anterolateral sides (Fig. 10B), and the T2 apical transverse band does not have lobe-like anterolateral extensions.Triepeolus fl avipennis is the only species in the T. verbesinae species group-containing species in which the pseudopygidial area of the female is distinctly circular (Fig. 10D)-that (usually) does not have an apical transverse band on T1.More commonly in this species, the T1 anterolateral patches of pale tomentum each have a short, medially directed posterolateral extension (Fig. 10B).

Etymology
Although Friese (1916) did not explain the etymology of his Epeolus fl avipennis, the specifi c epithet was presumably inspired by its yellow-orange wings, which do not reliably distinguish this species from similar-looking congeners.

Both sexes I
. Dark brown to black except as follows.Mandible with apical two-fi fths golden yellow (entirely dark brown/black in some non-type specimens).Mandible with middle fi fth (middle three-fi fths in holotype of T. bilineatus), labrum to some extent (except basomedially), scape and pedicel to some extent, F1 extensively, pronotal lobe, tegula, coxae to some extent, trochanters to tarsi (excluding brown meso-and metatibial spurs) partially to entirely, metasomal terga laterally, and metasomal sterna to some extent orange.F2 with orange spot basally.Fore wing membrane dusky subhyaline throughout.Hind wing membrane dusky subhyaline to hyaline.Pygidial plate to some extent reddish brown.

P
. Face with tomentum densest around antennal socket.Tomentum slightly sparser on clypeus; upper paraocular and frontal areas and vertexal area mostly exposed.Pronotal collar with tomentum Fig. 10.Triepeolus fl avipennis (Friese, 1916) uniformly pale yellow.Mesoscutum with well-defi ned paramedian band of pale-yellow tomentum, tapering slightly toward and attaining anterior margin; pale tomentum otherwise mostly restricted to lateral and posterior margins.Mesopleuron with off -white, appressed, branched setae; upper half densely setose, except behind pronotal lobe, with setae slightly sparser on hypoepimeral area; ventrolateral half sparsely setose.Metanotum with tomentum uninterrupted, uniformly off -white.Propodeal triangle mostly glabrous, with (pale) setae restricted to small lateral patches.Metasomal terga with bands of bright to pale-yellow tomentum.T1 with basal band separated medially into pair of anterolateral patches, each continuous with (and indistinguishable from) lateral longitudinal band and mesally convex, such that discal patch forming trapezoid or triangle with concave anterolateral sides; anterolateral patch with short, medially directed posterolateral extension in lectotype of E. fl avipennis; with medially interrupted apical transverse band in some non-type specimens.T2-T4 with medially narrowly interrupted apical transverse bands (in lectotype of E. fl avipennis) or medially narrowed apical transverse bands (in paralectotype of E. fl avipennis, holotype of T. bilineatus, and multiple non-type specimens); these bands without well-defi ned anterolateral extensions, although T2-T3 with faint lateral longitudinal bands of diff use off -white setae in types of E. fl avipennis and multiple non-type specimens.S2-S3 with apical transverse bands of white tomentum.

S
. Labrum and clypeus with punctures equally dense (most i < 1d); interspaces well defi ned, shining.Vertexal area densely punctate (most i < 1d).Mesoscutum, mesoscutellum, and axilla with punctures more or less equally dense and nearly contiguous (most i < 1d).Mesopleuron with punctures in upper half not much denser (most i < 1d) than in ventrolateral half (most i ≤ 1d); interspaces shining; punctures similar in size throughout.Discs of metasomal terga with punctures very fi ne, dense (i ≈ 1d), and evenly distributed; interspaces shining somewhat.

S
. Labrum with pair of small subapical denticles, each preceded by discrete longitudinal ridge.Pronotal collar rather short (medial length ~ ⅔ MOD).Mesoscutellum weakly bigibbous.Axilla extending little if at all beyond midlength of mesoscutellum; tip visible but somewhat blunt, mesally unattached to mesoscutellum for less than ⅓ medial length of axilla; lateral margin relatively straight.

Female
T5 with broadly convex apical margin and large patch of off -white to pale-yellow tomentum on each side lateral to pseudopygidial area or large, continuous patch (or band) of pale tomentum bordering and contacting pseudopygidial area.Pseudopygidial area circular, with basal crescent of dense, silvery setae; setae glossy, coppery, and sparser centrally; apical margin with row of dense, appressed and suberect coppery to silvery setae.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 slightly downturned apically, with apical fi mbria of coppery bristle-like setae; S5 otherwise covered in off -white tomentum.

Male
T5-T6 with complete or medially narrowly interrupted apical transverse bands of pale-yellow tomentum.Pygidial plate apically rounded and slightly downturned, with basal transverse ridge ill-defi ned and lateral margin somewhat sinuate.S4-S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved, coppery to silvery setae, not contrasting strongly with bands of preceding sterna.

Host records
Unknown.One vouchered male bears a label indicating that the specimen was collected in the presence of "Anthocopa on rock wall" near Metzquititlán in Hidalgo, Mexico, but an association between the two taxa seems very unlikely given that no osmiine bees have been confi rmed as hosts of Triepeolus (Rightmyer 2006).Rightmyer (2006)

Remarks
Rightmyer ( 2006) indicated that T. bilineatus and T. fl avipennis are likely conspecifi c.In one of the two studied (male) types of E. fl avipennis, the T2-T4 apical transverse bands of yellow tomentum are narrowly interrupted medially.In this species, the bands are more commonly complete, but specimens with medially narrowed and/or narrowly interrupted metasomal tergal bands have been observed from across the range of this species.In both the other type of E. fl avipennis and (female) holotype of T. bilineatus, the T2-T4 apical transverse bands are complete, albeit somewhat narrowed medially.The authors of the present study do not consider these to be distinct species, and T. bilineatus is herein synonymized under T. fl avipennis.
Since Friese (1916) did not explicitly designate a holotype, one of the two studied male syntypes (that which bears a red label that says "Type") is herein designated as the lectotype of E. fl avipennis.The other male, which bears an orange label that says "Typus", is recognized as a paralectotype.
In South America, this species is presently only known from a couple of localities along the Pacifi c coast of Colombia.Triepeolus fl avipennis has not yet been confi rmed from the Isthmus of Panama and consequently shows a disjunct distribution (Fig. 1E); however, its presence there is expected based on its occurrence in northern South America and the Northern Triangle of Central America.(Holmberg, 1886) Figs 1F, 3B, 11, 13B Doeringiella nemoralis Holmberg, 1886: 280 (♀).

Diagnosis
The following morphological features in combination tell T. nemoralis apart from all other South American Triepeolus: the T1 basal band is arched, continuous with (and indistinguishable from) the lateral longitudinal bands, and mesally concave on each side, such that the discal patch is semicircular (Fig. 11B); the mesoscutum has a large anteromedial ovate patch of yellow tomentum (Fig. 3B), which ONUFERKO T.M. et al., A revision of South American Triepeolus (Hymenoptera) may be sparser medially such that the patch is suggestive of ill-defi ned paramedian bands (Fig. 11B); and T2-T4 have complete apical transverse bands of yellow tomentum (Figs 3B,11B).Triepeolus nemoralis most closely resembles specimens of T. alvarengai without an apical transverse band on T1 and T. mexicanus (Cresson, 1878), the latter of which is known only from North and Central America, but in T. alvarengai the mesoscutum has well-defi ned paramedian bands and in T. mexicanus pale tomentum on the mesoscutum is restricted to the lateral and posterior margins.Males of T. nemoralis also closely resemble those of T. fl avipennis, but in T. fl avipennis the mesoscutum has well-defi ned paramedian bands and the pair of anterolateral patches of pale tomentum on T1 are mesally convex, such that the discal patch forms a trapezoid or triangle with concave anterolateral sides.This species is also very similar in overall appearance to Epeolus luteipennis, and in both species the mesoscutum has a large anteromedial patch of yellow tomentum as opposed to well-defi ned paramedian bands, but both sexes of T. nemoralis are easily told apart from any similar-looking Epeolus by their simple mandibles; in E. luteipennis and all other South American Epeolus, the mandibles each have a distinct preapical tooth.

Etymology
Although Holmberg (1886) did not explain the etymology of his Doeringiella nemoralis, the specifi c epithet seemingly alludes to the habitat (grove or woodland) in which the type of this species was collected.

Both sexes I
. Dark brown to black except as follows.Mandible with middle quarter in basal half reddish brown (basal half entirely reddish brown in some non-type specimens).Scape to some extent, pedicel and F1 extensively, and tegula orange.F2 with orange spot basally.Antenna entirely dark brown in some non-type specimens.Fore wing membrane dusky subhyaline throughout.Hind wing membrane dusky subhyaline to hyaline.Legs to some extent reddish brown in holotype of E. merus; dark brown to black in some non-type specimens.Pygidial plate reddish brown. .Face with tomentum densest around antennal socket.Tomentum slightly sparser on clypeus; upper paraocular and frontal areas and vertexal area mostly exposed.Pronotal collar with tomentum pale yellow laterally and black medially (uniformly bright yellow in some non-type specimens).Mesoscutum with large anteromedial ovate patch of pale-yellow tomentum, slightly separated from anterior margin (setae rather diff use and patch thus ill-defi ned in holotype of E. merus; well-defi ned in some non-type specimens); pale tomentum otherwise mostly restricted to lateral and posterior margins.Mesopleuron with off -white, appressed, branched setae; densely setose just below scrobal groove (upper half otherwise sparsely setose); ventrolateral half nearly bare, except along margins.Metanotum with tomentum uninterrupted, uniformly off -white (black medially in some non-type specimens).Propodeal triangle mostly glabrous, with (pale) setae restricted to small lateral patches.T1 with basal transverse band of pale-yellow tomentum complete (separated medially into pair of anterolateral patches in some non-type specimens), continuous with (and indistinguishable from) lateral longitudinal band, forming arch around semicircular discal patch.T2-T4 with complete apical transver se bands of bright yellow tomentum without well-defi ned anterolateral extensions, although T2-T3 with faint lateral longitudinal bands of diff use off -white setae in some non-type specimens.S2-S3 with apical transverse bands of white tomentum.

S
. Labrum with pair of small subapical denticles.Pronotal collar rather short (medial length ~ ⅔ MOD).Mesoscutellum moderately bigibbous.Axilla extending beyond midlength of mesoscutellum but not as far back as its posterior margin; tip distinctly pointed and hooked (i.e., concave along medial margin), but mesally unattached to mesoscutellum for less than ⅖ medial length of axilla; lateral margin somewhat sinuate.

Female
Mesoscutum with ill-defi ned paramedian band among diff use pale-yellow setae in some non-type specimens.T5 with concave apical margin and large patch of pale-yellow tomentum on each side lateral to pseudopygidial area.Pseudopygidial area with underlying integument extensively orange, forming rounded triangle with concave sides, with orange spinelike setae laterally.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 straight in lateral view, with apical fi mbria of coppery bristle-like setae; S5 otherwise covered in off -white tomentum.

Distribution
Northern and eastern South America (Fig. 1F).

Host records
Unknown.

Remarks
The type of D. nemoralis is meant to be at the MACN but has been destroyed (Moure & Melo 2007).In a revision of Doeringiella, Roig-Alsina (1989) indicated that "D.nemoralis should be called Triepeolus nemoralis (Holmberg) (new combination)" based on its description.The ill-defi ned spots (of pale tomentum) on the mesoscutum, (single) medially narrowed yellow band on T1, complete golden bands on T2-T4, and orange-squamous T5 (in reference to the pseudopygidial area and underlying integument coloration) describe a single species of Triepeolus in South America (in the T. simplex species group).This species was later described under the name Epeolus merus (by Brèthes 1909) from a male specimen, supposedly from Alto Paraguay in the Paraguayan Chaco (or Western Region), but this does not correspond with the locality given on the collection label (i.e., San Bernardino, Paraguay) (Fig. S10D in Supp.fi le 2).Although male, the holotype of E. merus closely matches the original description of D. nemoralis (based on the female) and both are regarded as belonging to the same species, so E. merus is herein established as a junior synonym of D. nemoralis (= T. nemoralis).

Diagnosis
Triepeolus osiriformis can be told apart from all other South American Triepeolus by the reddish brown (as opposed to black) axillae and mesoscutellum (Figs 12A-C, 13C).Additionally, much of the head, rest of the mesosoma, and metasoma are also reddish brown in T. osiriformis 15A).In this respect and in terms of the patterns of pubescence on the metasoma, T. osiriformis superfi cially resembles Rhinepeolus rufi ventris (Friese, 1908), from which it is easily told apart by the presence of well-defi ned paramedian bands (as opposed to a median longitudinal strip of pale, short, appressed setae) on the mesoscutum as well as its mutic (i.e., non-as opposed to distinctly bituberculate) mesoscutellum.

Etymology
The specifi c epithet was inspired by the elongate (male) metasoma, which in the original description was said to be "aff ecting the shape of [the bee genus] Osiris" (Schrottky 1910).lectotype of E. luteipes, and some non-type specimens), mesoscutellum, axilla, metanotum, mesopleuron extensively (more so in upper half than in ventrolateral half), and propodeum to some extent (in lectotype of E. luteipes and some non-type specimens) reddish brown.Fore wing membrane subhyaline, apically dusky.Hind wing membrane dusky subhyaline to hyaline.

P
. Face with tomentum densest around antennal socket.Tomentum slightly sparser on clypeus; upper paraocular and frontal areas and vertexal area mostly exposed.Pronotal collar with tomentum uniformly off -white.Mesoscutum with well-defi ned paramedian band of pale-yellow tomentum, tapering slightly toward and attaining anterior margin; pale tomentum otherwise mostly restricted to lateral and posterior margins.Mesopleuron with off -white, appressed, branched setae; densely setose except for two sparsely setose circular patches (one beneath base of fore wing (hypoepimeral area) and slightly larger one in ventrolateral half of mesopleuron).Metanotum with tomentum sparser medially, off -white laterally and reddish brown medially (uniformly off -white in holotype of E. paraensis and some non-type specimens).Propodeal triangle mostly glabrous, with (off -white to dark brown/gray) setae restricted to small lateral patches.Metasomal terga with bands of white to pale-yellow tomentum.T1 with basal transverse band complete or narrowly interrupted medially, apical transverse band narrowed or interrupted medially, transverse bands subparallel, discal patch transversely oblong.T2-T4 with medially interrupted apical transverse bands, that of T2 with pair of basomedially convergent anterolateral extensions.S2-S3 with apical transverse bands of white tomentum.

S
. Labrum with pair of small subapical denticles, each preceded by discrete longitudinal ridge.Pronotal collar short (medial length ~ ½ MOD).Mesoscutellum weakly bigibbous, with lower posterior margin forming shelf-like ridge overhanging metanotum.Axilla extending beyond midlength of mesoscutellum but not as far back as its p osterior margin; tip distinctly pointed and hooked (i.e., concave along medial margin), mesally unattached to mesoscutellum for ~ ⅓-½ medial length of axilla; lateral margin somewhat sinuate.

Female
T5 with broadly convex apical margin and large patch of white to off -white tomentum on each side lateral to pseudopygidial area.Pseudopygidial area circular, with setae glossy, predominantly grayish brown, and sparser centrally; apical margin with row of dense, appressed and suberect coppery to silvery setae.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 straight in lateral view, with apical fi mbria of coppery bristle-like setae; S5 otherwise covered in off -white tomentum.

Remarks
This species was previously known by the name T. nobilis (Friese, 1908).However, Rightmyer (2008) recognized the primary type of Epeolus nobilis (original combination) as conspecifi c with that of T. intrepidus (Smith, 1879), a species from Mexico and the southwestern United States, and established the former as a junior synonym of the latter.Although Friese (1908) described E. nobilis in a paper on bees of Argentina, T. intrepidus is not known to occur anywhere in South America.According to Friese (1908), the types of E. nobilis came from an old collection of Hermann Burmeister in Argentina.The (male) lectotype of E. nobilis and a conspecifi c female at the ZMB each bear a label that says 'Argentini 1900', but this information does not conform with the expected collection locality or date.Most likely, the specimens were erroneously presumed to have originated in Argentina having been sent to Germany from the Burmeister collection at the MACN in Buenos Aires, where there are still two specimens of T. intrepidus (one female and one male) that might belong to the same series.Interestingly, whereas the female lacks a collection label, the male bears a small, green, poorly handwritten label indicating the word Mexico.The lectotype of E. nobilis has a separate label indicating only the letter M, which appears to be original and lik ely stands for Mexico.As Burmeister died in 1892, the specimens could not have been collected by him in 1900, which may instead indicate the year the specimens were received by Friese.Presumably, Moure (1955) confused T. nobilis with T. osiriformis based on Friese's (1908) description of the former having a red mesoscutellum and there being only one species of Triepeolus in South America in which the mesoscutellum is red.
Epeolus osiriformis Schrottky, 1910 was described from both sexes.The MZUSP has a male labeled as the type and referred to as such by Moure (1955).Rightmyer (2008) referred to this specimen as the holotype; however, since Schrottky (1910) did not explicitly designate a holotype, the specimen is herein designated as the lectotype of E. osiriformis.Moure (1955) regarded Epeolus luteipes Friese, 1916 andE. paraensis Friese, 1925 as synonymous with E. (now T.) osiriformis.The authors of the present study examined the primary types of E. osiriformis, E. luteipes, and E. paraensis and agree with Moure's treatment.Epeolus luteipes was described from both sexes.A female syntype at the ZMB, which bears an orange label that says "Typus", is herein designated as the lectotype of E. luteipes.(Ashmead, 1900) Figs 1H, 4D, 14

Diagnosis
The following morphological features in combination tell T. rufotegularis apart from all other South American Triepeolus: the T1 discal patch is reniform, T1-T4 (in females) or T1-T6 (in males) have medially interrupted bands of white to off -white tomentum, and the T2 apical transverse bands do not have lobe-like anterolateral extensions (Fig. 14A-C).In terms of the patterns of pubescence on the mesosoma and metasoma, T. rufotegularis most closely resembles T. verbesinae, a North American species, but in T. verbesinae the T1 discal patch is triangular with concave sides, the metasomal tergal bands are pale yellow, the T2 apical transverse bands have lobe-like anterolateral extensions, and the female S5 is strongly (as opposed to slightly) downturned apically.Males of T. rufotegularis are also similar to those of T. tuberculifer sp.nov., but in T. tuberculifer sp.nov. the pro-and mesotrochanters are distinctly (as opposed to non-) tuberculate, the free portion of each axilla is more (as opposed to less) European Journal of Taxonomy 931: 1-50 (2024) metasomal terga with punctures very fi ne, dense (i ≈ 1d), and evenly distributed; interspaces shining somewhat.

S
. Labrum with pair of small subapical denticles, each preceded by discrete longitudinal ridge.Pronotal collar rather short (medial length ~ ⅗ MOD).Mesoscutellum weakly bigibbous.Axilla not extending beyond midlength of mesoscutellum; tip visible but somewhat blunt, mesally unattached to mesoscutellum for less than ⅓ medial length of axilla; lateral margin relatively straight.

Female
T5 with broadly convex apical margin and large patch of white to off -white tomentum on each side lateral to pseudopygidial area.Pseudopygidial area circular, with setae glossy, predominantly grayish brown, and sparser centrally; apical margin with row of dense, appressed and suberect coppery to silvery setae.Pygidial plate orange in part and apically truncate (T6 entir e ly retracted in lectotype; described from non-type specimen).S4 with apical transverse band of white tomentum.S5 slightly downturned apically, with apical fi mbria of coppery bristle-like setae; S5 otherwise covered in brown tomentum.

Male
T5-T6 with medially interrupted apical transverse bands of off -white tomentum.Pygidial plate reddish brown and apically rounded and slightly downturned, with basal transverse ridge rather ill-defi ned and lateral margin sinuate.S4-S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved setae; coppery to silvery laterally (more so on S4 than S5), brown and contrasting strongly with bands of preceding sterna medially.

Distribution
Northern South America to Saint Vincent in the Lesser Antilles (Fig. 1H).

Host records
Unknown.

Floral records
Unknown.

Remarks
Although Ashmead (1900) described only the female of this species, a syntype of E. rufotegularis at the NHMUK, which bears a circular label that says "Type", was incorrectly sexed and is a male.The description of the male of T. rufotegularis is published here for the fi rst time.Since Ashmead (1900) did not explicitly designate a holotype among the eight specimens comprising the type series, a female syntype at the USNM, which bears a red label that says "Type", is herein designated as the lectotype of E. rufotegularis.transverse bands interrupted medially (former somewhat mo re widely than latter) and subparallel, discal patch transversely oblong.T2-T4 with medially interrupted apical transverse bands, that of T2 with pair of b asomedially convergent anterolateral extensions.S2-S3 with apical transverse bands of white tomentum.

S
. Labrum and clypeus with punctures equally dense and nearly contiguous (most i < 1d).Clypeus without glabrous midline in holotype and female paratype, but with incomplete and very short glabrous midline extending from upper margin down to < ⅓ length of clypeus in (male) allotype.Vertexal area somewhat sparsely punctate (some i > 2d), especially around ocelli.Mesoscutum densely punctate (most i ≤ 1d) but interspaces well defi ned, shining.Mesoscutellum and axilla with punctures equally dense and nearly contiguous (most i < 1d).Mesopleuron with punctures in upper half not much denser (most i < 1d) than in ventrolateral half (most i ≤ 1d); interspaces shining; punctures similar in size throughout.Discs of metasomal terga with punctures very fi ne, dense (i ≈ 1d), and evenly distributed; interspaces dull due to tessellate surface microsculpture.

Female
T5 with concave apical margin and large patch of off -white tomentum on each side lateral to pseudopygidial area.Pseudopygidial area with underlying integument reddish brown in part; forming rounded triangle with concave sides; with brown erect/suberect setae basally and brown spinelike setae laterally.Pygidial plate apically truncate.S4 with apical transverse band of white tomentum.S5 straight in lateral view, with patch of off -white tomentum submedially (absent in paratype) and apical fi mbria of coppery bristle-like setae; S5 otherwise covered in brown tomentum.

Male
T5-T6 with medially narrowed or narrowly interrupted apical transverse bands of off -white tomentum.Pygidial plate relatively fl at and apically rounded.S4-S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved, coppery to silvery setae, not contrasting strongly with bands of preceding sterna.

Host records
Unknown.

Floral records
Unknown.

Remarks
This species was fi rst documented in Rightmyer's (2006) dissertation, wherein it was referred to as "sp.169".Rightmyer (2008) included the species in a key to Triepeolus from South America and the Caribbean but under the name Triepeolus n. sp. 2. Although Rightmyer (2006Rightmyer ( , 2008) ) treated the species, then based on a single, male specimen (herein designated as the allotype of T. tuberculifer sp.nov.), as a member of the T. verbesinae species group, the subsequent discovery of the female confi rms its true placement in the T. simplex species group.

Discussion
In South America, a total of nine species of Triepeolus are confi rmed, most of which are restricted to the northern and western parts of the continent.Colombia and Peru have the highest numbers of species, with eight recorded between the two countries.Whereas there is strong phylogenetic and biogeographic support for a South American (or at least Neotropical) origin for Epeolini and most of its constituent genera, Triepeolus, like the related genus Epeolus, likely originated in North America and subsequently dispersed to South America.This is suggested not only by the comparatively low levels of species richness of both genera in South America but also several other factors as follows.
Only two species groups are represented in South America-the T. simplex species group, which includes T. alvarengai, T. nemoralis, and T. tuberculifer sp.nov., and the T. verbesinae species group, which includes all the others-both of which exhibit their greatest diversity in North America (Rightmyer 2006).Although taxon sampling has been limited for molecular phylogenetic and phylogenomic analyses, phylogenies based on morphological (Rightmyer 2004), combined molecular and morphological (Onuferko et al. 2019), and phylogenomic (Sless et al. 2022) datasets have consistently placed the Palearctic species as sister to the rest of the genus, suggesting that Triepeolus originated somewhere in the Holarctic region.That Triepeolus is represented by only two species in the Palearctic (versus > 100 in the Nearctic) further suggests a North American origin.However, it should be noted that none of the molecular phylogenies to date have included members of the T. simplex species group.A more recent arrival in South America would also explain the disparity in diversity there between Triepeolus and the tribe Eucerini (Hymenoptera: Apidae), which includes most of the known hosts of Triepeolus yet also exhibits higher generic diversity in South America than in North America (Rightmyer 2004;Michener 2007).
Similarly, almost all species of Epeolus in South America (E.luteipennis excepted) belong to a single species group, and only three (of the six) species in the genus represented on the continent are endemic (Onuferko 2019).The species in this group share several morphological peculiarities, and, as a result, they have at various times been regarded as belonging to a separate genus, Trophocleptria Holmberg, 1886.However, the most comprehensive phylogenetic and biogeographic study of Epeolus to date revealed a monophyletic Trophocleptria clade nested deeply within Epeolus and inferred a Nearctic origin for the species group (Onuferko et al. 2019).

Diagnosis for Triepeolus in South America Species
of Triepeolus are non-metallic epeoliform bees that closely resemble various other cleptoparasitic bees, especially the related genera Doeringiella, Epeolus, Pseudepeolus, Rhinepeolus, and Rhogepeolus.