Phylogenetic analysis and systematics of the Acrapex unicolora Hampson species complex (Lepidoptera, Noctuidae, Noctuinae, Apameini), with the description of fi ve new species from the Afrotropics

Ten morphologically similar species of Acrapex Hampson, 1891 (Lepidoptera, Noctuidae, Noctuinae, Apameini) from Central and Eastern Africa are reviewed, including fi ve new species: Acrapex kafula le Ru sp. nov., A. kavumba le Ru sp. nov., A. kiakouama le Ru sp. nov., A. miscantha le Ru sp. nov. and A. simillima le Ru sp. nov. Evidence is provided to transfer the monotypic genus Poecopa Bowden, 1956 to the genus Acrapex. Host plants of fi ve species are recorded, some of them for the fi rst time. Acrapex kavumba sp. nov., A. miscantha sp. nov. and A. simillima sp. nov. were found on one host plant each. Acrapex mediopuncta, previously reported in West Africa from Pennisetum purpureum Schumach., Rottboellia compressa L., Setaria megaphylla (Steud) Dur. & Schinz. and Sorghum arundinaceum (Desv.) Stapf, was only found from S. megaphylla in Central Africa. Larvae of Acrapex unicolora were collected on Andropogon gayanus Kunth, Chrysopogon zizanoides (L.) Roberty, Cymbopogon schoenanthus subsp. proximus (Hochst. ex A.Rich.) Maire & Weller, Cymbopogon pospischiilii (K.Schum.) C.E.Hubb., Hyparrhenia diplandra (Hack.) Stapf and Setaria sphacelata (Schumach.) Moss. We also conducted molecular phylogenetic analyses (using maximum likelihood) and molecular species delimitation analyses on a comprehensive sample of 61 specimens belonging to eight of the studied species. Molecular phylogenetic analyses provided additional evidence of the synonymy of Acrapex and Poecopa, whereas molecular species delimitation analyses support the validity of the fi ve newly described species and unravel another potential new species, only collected in the larval stage.


Introduction
Among the African noctuid stem borers of the subtribe Sesamiina (Lepidoptera, Noctuidae, Noctuinae, Apameini) the genus Acrapex Hampson, 1891 consists of about 90 species that are mostly distributed in the Afrotropical region (Le . Until recently, very little was known about Acrapex host preferences as specimens had been obtained mainly from light trap collections. Extensive surveys conducted since 2004 (Le Ru et al. 2006Ru et al. a, 2006bOng'amo et al. 2006Ong'amo et al. , 2013Ong'amo et al. , 2014Ndemah et al. 2007;Matama-Kauma et al. 2008;Moolman et al. 2014) in several sub-Saharan countries, targeting wild habitats rich in Poaceae and combining infested host plant collections and light traps, allowed us to obtain several hundred specimens of Acrapex. A recent study by Le  focused on a LE RU B. et al., Contribution to Acrapex systematics 3 small group of morphologically related species belonging to subsets of two (groups B and C) of the four morphological groups that have been defi ned by Berio (1973) based on male genitalia. The latter study unravelled no less than six new species, thus suggesting that the species diversity of Acrapex in Sub-Saharan Africa is greatly underestimated (Le ).
In the present study, we focus on a species complex that consists of A. unicolora Hampson, 1910 and nine morphologically related species (fi ve of which are new to science). These species constitute another subset of group B as defi ned by Berio (1973); the other subset corresponds to the A. stygiata (Hampson, 1910) group . Our subset of interest (hereafter referred to as the A. unicolora group) consists of A. cuprescens (Hampson, 1910), A. malagasy Viette, 1967, A. parvaclara Berio, 1973 (Bowden, 1956) comb. nov., A. kafula le Ru sp. nov., A. kavumba le Ru sp. nov., A. kiakouama le Ru sp. nov., A. miscantha le Ru sp. nov. and A. simillima le Ru sp. nov. It is characterised by the following combination of characters: (i) valve short and broad at basal half, cucullus rounded and tufted, with medium size hairs; (ii) coastal margin slightly broadened on the inner side and produced into a tooth-shaped spine, pointed and slightly curved inwardly; (iii) juxta large, plate-like, widening to the top without sclerotisation; (iv) aedeagus short, stout, slightly curved, with two lateral areas adorned with short setae; (v) vesica hand-shaped, with a tuft of cornutus, needle-shaped.
For this study we include the description of the fi ve new species which have been cross-checked against all Acrapex types preserved in museums to avoid the coinage of synonymies. We also provide a supplemental description for fi ve species of the A. unicolora group, with female genitalia presented for the fi rst time for A. cuprescens, A. parvaclara and A. unicolora. Finally, we conduct phylogenetic analyses on a multi-marker molecular dataset (four mitochondrial gene fragments and two nuclear gene fragments) to explore species boundaries and investigate the phylogenetic placement of several species.

Sampling
Sampling of visually damaged grasses (Poales) in Eastern and Southeastern Africa was conducted over ten years (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) to collect the larval stages of noctuid stem borers within their wild host plants (Le Ru et al. 2006a, 2006b. Larvae were reared on an artifi cial diet (Onyango & Ochieng'Odero 1994) until pupation and the emergence of adults (Le Ru et al. 2006aRu et al. , 2006b. A total of 271 larvae belonging to the group of interest were sampled in the localities listed in Table 1. In addition, 185 adults from this species group were collected in light traps set up in Cameroon, Kenya, the Republic of the Congo, Tanzania, Uganda and Zambia. The morphological study is based on 72 adult specimens belonging to 10 Acrapex species collected in 46 localities in seven countries: Cameroon, the Democratic Republic of the Congo, Kenya, the Republic of the Congo, Tanzania, Uganda and Zambia (see also Le Ru et al. 2014). Plant specimens were identifi ed by Simon Mathenge (Botany Department, University of Nairobi, Kenya).

Morphological study
Genitalia were dissected after immersion of the end of the abdomen in a boiling 10% potash bath for a few minutes, then cleaned, immersed in absolute alcohol for a few minutes and mounted on slides in Euparal (after separating the aedeagus from the rest of the genitalia in the male).
Collected insects were identifi ed by comparison with types and specimens housed in the following institutions: BMNH = Natural History Museum, London, UK MCSN = Museo Civico di Storia Naturale di Milano, Milan, Italy The holotypes of the new species were deposited in MNHN and paratypes were deposited in MNHN and NMKE.

DNA Extraction and Sequencing
For this study, 67 specimens of Acrapex were selected for the molecular analyses, including 60 individuals from the A. unicolora group. We also included one representative of the A. stygiata species group (A. stygiata) and fi ve representatives of the A. albivena species group (A. albivena Hampson, 1910, A. salmona Le Ru, 2014, A. sporobola Le Ru, 2014, A. syscia Fletcher, 1961and A. yakoba Le Ru, 2014. As outgroups, we included representatives of four other genera in the subtribe Sesamiina based on the results of several molecular studies (Toussaint et al. 2012;Le Ru et al. 2014). DNA was extracted from hind legs using Qiagen DNAeasy tissue kits (Qiagen, Hilden, Germany). Polymerase chain reaction (PCR) amplifi cations were conducted for four mitochondrial gene fragments: a 681 bp region of the cytochrome c oxidase subunit I (COI), 1038 bp of cytochrome b (Cytb), 389 bp of the ribosomal 12S RNA (12S) and 539 bp of the ribosomal 16S RNA (16S). Two nuclear gene regions were also sequenced: 835 bp of the 28S ribosomal DNA (28S) and 1230 bp of the elongation factor-1α (EF1α). For both genes we used the primers and settings detailed in Kergoat et al. (2012). Resulting PCR products were processed by the French sequencing center Genoscope using a BigDye v. 3.1 sequencing kit and Applied 3730xl sequencers. Both strands were sequenced for all specimens to minimize PCR artefacts and ambiguities. Sequences of complementary strands were automatically edited and reconciled using Geneious v. 5.1 software (available from www.geneious.com/). All the sequences generated in this study were deposited in GenBank (see Appendix for the accession numbers). Unlike the sequences of coding genes (COI, Cytb and EF1α), the sequences of ribosomal genes (12S, 16S and 28S) were variable in length. Their alignment was accomplished using MAFFT v. 7 (Katoh & Standley 2013)

Phylogenetic and molecular species delimitation analyses
Maximum likelihood (ML) was used to infer phylogenetic relationships on the combined dataset. To improve phylogenetic accuracy we carried out partitioned analyses (Nylander et al. 2004). Partitions and substitution models were determined using PartitionFinder v. 1.1.1 (Lanfear et al. 2012), based on the corrected Akaike information criterion (AICc). Maximum Likelihood analyses were carried out with the recently developed IQ-TREE (Nguyen et al. 2015), using the web server at http://iqtree.cibiv. univie.ac.at/. IQ-TREE optimises the ML search by focusing on local optima and comparing them to fi nd the best ML tree, and it has been shown to potentially outperform other ML programs (Nguyen et al. 2015). Based on the AICc results we used four partitions (Table 2), with the corresponding models of substitutions being determined using the Auto function on the IQ-TREE web server, following the authors' recommendations. Clade support was then assessed under IQ-TREE using ultrafast bootstrap replicates (Minh et al. 2013) (1000 replicates were used); nodes supported by bootstrap values (BV) > 70% were considered strongly supported following Hillis & Bull (1993).
For molecular species delimitation procedures, we relied on Poisson-tree-processes (PTP) analyses (Zhang et al. 2013). With the PTP model, speciation or branching events are modelled in terms of number of substitutions (represented by branch lengths). This approach has the advantage of not requiring the inference of an ultrametric tree, which is usually a time-consuming and potentially error-prone process (Astrin et al. 2012;Tang et al. 2014); it has also recently been used in several noctuid groups, providing relevant results from a morphological and ecological point of view (Le Ru et al. , 2015Dumas et al. 2015). Corresponding analyses were conducted on the web server of the Exelixis Lab (http:// species.h-its.org/ptp/), with default settings and using the best ML tree from the IQ-TREE analysis.

Diagnosis
Male easily separated from males of other species of the group by the short and stout, slightly curved aedeagus and the vesica with a tuft of needle-shaped, horizontally oriented cornutus (Fig. 2I); female easily separated from females of other species of the group by the small sclerotized area of the ductus bursae on ostial side, half the length of the ductus bursae, and with the ventral plate of the ostium bursae sclerotized, slightly bilobate and invaginated on the back side (Fig. 3A).

Description
The descriptions of the external features of the male holotype and of the female holotype of B. rufi dorsata, by Hampson (1910) were accurate. The male looks very similar to the female; however, the general shape of the female's fore wing is more elongated at the apex (Figs 1A-B, E-F). Descriptions of the genitalia of both sexes were not provided by Hampson (1910).
invaginated on back side, dorsal plate large, broad and weakly sclerotized. Ovipositor lobes relatively short and wide (twice as long as wide), with bluntly pointed apex, dorsal surface bearing numerous short and stout setae.

Diagnosis
Male easily separated from males of other species of the group by the shovel-shaped uncus (at the apex) and the distal part of the aedeagus (grooved-shaped), with the vesica having a basal tuft of needleshaped cornutus, pointed downward ( Fig. 2B, J). Female easily separated from females of other species of the group by the very short ductus bursae, with a strongly sclerotised funnel-shaped connection with the ostium; antrum sclerotized, with a large, broad ventral plate, slightly bilobate, widening to the front, the anterior part shaped like a thin lip and more sclerotized than the posterior part, slightly concave ( Fig. 3B).

Etymology
Named after the village of Kafulo in Zambia.

Description
Both sexes look similar; however, general shape of female fore wing more elongated at apex than in male and fore wings paler in females ( Fig. 1G-J); antennae bright fuscous dorsally and ochreous ventrally, fi liform in female and slightly ciliate in male; fl agellum adorned dorsally with black scales, palpus cupreous brown, eyes fuscous. Head and base of thorax brown, thorax becoming gradually fuscous; legs brown-ringed with buff, buff on inner surface; abdomen fuscous, irrorated with buff scales. FORE WING. Ground colour ochreous in both sexes, suffused with fuscous scales, more heavily along veins and costal area, particularly in males; reniform indicated by a few white scales, preceded by some brown scales; longitudinal brown median fascia along lower external margin of cell, ending obliquely at apex; veins below cell adorned with white, fuscous and brown scales; postmedial row of white spots on veins; row of black elongated spots between veins on margin; fringe whitish externally, fuscous suffused with brown internally. Underside of fore wing with ground colour fuscous, densely suffused with brown scales.
HIND WING. Ground colour white, veins slightly irrorated, with fuscous scales, costa and apex more heavily suffused with fuscous scales; hind wing of males much more suffused with fuscous scales than in females; fringe white, suffused with fuscous and adorned with narrow fuscous line. Underside of hind wing white, suffused with fuscous scales but much more heavily on costa and apex; veins slightly irrorated, with fuscous scales.
MALE GENITALIA (Fig. 2B, J). Uncus long, widening in distal third, shovel-shaped at apex, tufted with long hairs on upper side. Tegumen with medium-sized rounded penniculi, vinculum pointed, with mediumsized triangular saccus, valves short and broad, cucullus rounded and tufted with medium-sized hairs, coastal margin slightly broadened on inner side and produced into strong, tooth-shaped spine, strongly sclerotized at apex, pointed and slightly curved inwardly; juxta large, plate-like, without sclerotisation. Aedeagus short, slightly curved, with two lateral areas adorned with short setae; hand-shaped vesica with basal tuft of needle-shaped cornutus, pointed downward. FEMALE GENITALIA (Fig. 3B). Corpus bursae elongated ovoid and globular without signa; ductus bursae very short, with strongly sclerotised, funnel-shaped connection with ostium; antrum sclerotized, with large, broad ventral plate, slightly bilobate, widening to the front, anterior part shaped like a thin lip, more sclerotized than posterior part, slightly concave; dorsal plate small, weakly sclerotized. Ovipositor lobes relatively short (2.2 times as long as wide), with pointed apex, dorsal surface bearing numerous short and stout setae.

Bionomics
Biology unknown. The moths were caught in a light trap in grasslands near marshes.

Distribution
Cameroon, Kenya, the Republic of the Congo, Tanzania, Uganda and Zambia. Moths were found in a mosaic of lowland rainforest and secondary grassland (Mosaic #11), in a mosaic of Zambezian dry evergreen forest and wetter miombo woodland (Mosaic #21), in a mosaic of East African evergreen bushland and secondary Acacia wooded grassland (Mosaic #45) and in undiffentiated montane vegetation (Mosaic #19) (White 1983) (Fig. 4)

Description
Only the male is known (Fig. 6A-B); antennae cupreous brown dorsally and ochreous ventrally, slightly ciliate; fl agellum adorned dorsally with white scales, palpus cupreous brown, adorned with white scales, eyes fuscous. Head and base of thorax brown, thorax becoming gradually ochreous; legs brown-ringed with white; abdomen brown irrorated with fuscous scales, extremity of abdomen densely suffused with buff scales. FORE WING. Ground colour dark ochreous, suffused with fuscous and brown scales, more heavily along veins and in costal area; reniform indicated by few white scales, preceded by some brown scales; longitudinal brown median fascia along lower external margin of cell, ending obliquely at apex; veins below cell adorned with white, fuscous and brown scales; postmedial row of white spots on veins; row of black elongated spots between veins on margin; fringe whitish externally, ochreous suffused with brown internally. Underside of fore wing with ground colour brown, suffused with fuscous scales on costa.
HIND WING. Uniformly brown; fringe white suffused with fuscous and adorned with narrow fuscous line. Underside of hind wing brown, suffused with fuscous scales.
MALE GENITALIA (Fig. 2C, K). Uncus long, widening in distal third, truncated at apex, tufted with long hairs on upper side. Tegumen with medium-sized rounded penniculi, vinculum pointed, with mediumsized triangular saccus, valves short and broad, cucullus spoon-shaped and tufted with medium size hairs, coastal margin slightly broadened on inner side and produced into narrow, straight, long lobe, roundly pointed; juxta oblong, pear-shaped, with long and wide neck, elongate bifi d. Aedeagus short, slightly curved, with two lateral areas adorned with short setae; turn of hand-shaped vesica with large tuft of needle-shaped cornutus.

Bionomics
One larva was collected at the bottom of a stem of a Hyparrhenia sp. growing in grasslands near marshes (Table 3); like many species of Acrapex, A. kavumba sp. nov. is a markedly hygrophilous species. Unfortunately, no pictures were taken before pupation. All the moths were caught in a light trap in grasslands near marshes.

Diagnosis
Male easily separated from males of other species of the group by the uncus being shovel-shaped at the apex and by the large, plate-like juxta, with a narrow pyriform base and a long and widening, slightly sclerotised neck (Fig. 2D); female easily separated from females of other species of the group by having the antrum strongly sclerotized, with a large, broad ventral plate, bilobate, widening to the front, anterior part shaped like a fl eshy lip, the posterior part concave (Fig 3C).

Etymology
Named after Kiakouama, the technician who collected this species in the Republic of the Congo.

Description
Both sexes look similar; however, the general shape of the female fore wing is more elongated at the apex than in the male and is paler (Fig. 6C-F); antennae bright ochreous dorsally and ochreous ventrally, fi liform in female and slightly ciliate in male; fl agellum adorned dorsally with grey scales, palpus ochreous grey, eyes fuscous brown. Head and base of thorax bright brown, thorax ochreous; legs ochreous, ringed with grey white; abdomen grey. FORE WING. Ground colour bright ochreous in both sexes, suffused with fuscous and brown scales, more heavily along veins and costal area, particularly in male; reniform indicated by few white scales, surrounded by some brown scales; longitudinal brown median fascia along lower external margin of cell, ending obliquely at apex; veins below cell adorned with white and fuscous scales; row of black elongated spots between veins on margin; fringe grey externally, ochreous suffused with fuscous internally. Underside of fore wing with ground colour ochreous, densely suffused with brown scales. HIND WING. Ground colour pale ochreous in male, more whitish in female; veins slightly irrorated, with fuscous scales, costa and apex more heavily suffused with fuscous scales; hind wing of male much more suffused with fuscous scales than that of female; fringe pale ochreous, suffused with fuscous and adorned with narrow fuscous line. Underside of hind wing pale ochreous in male, more whitish in female, suffused with brown scales but much more heavily on costa and apex; veins slightly irrorated with pale fuscous scales.
MALE GENITALIA (Fig. 2D, K). Uncus long, widening in distal third, shovel-shaped at apex, tufted with long hairs on upper side. Tegumen with medium-sized rounded penniculi, vinculum pointed, with medium-sized triangular saccus, valves short and broad, cucullus rounded and tufted, with medium-sized hairs, coastal margin slightly broadened on the inner side and produced into strong tooth-shaped spine, strongly sclerotized at apex, pointed and curved inwardly; juxta large, plate-like, base pyriform, without sclerotization, with long and widening, slightly sclerotized neck. Aedeagus short, slightly curved, with two lateral areas adorned with short setae; hand-shaped vesica with basal tuft of needle-shaped cornutus, pointed obliquely downward. FEMALE GENITALIA (Fig. 3C). Corpus bursae long and globular, without signa; ductus bursae very short, with strongly sclerotized funnel-shaped connection with ostium; antrum strongly sclerotized, with large, broad ventral plate, bilobate, widening to the front, anterior part shaped like a fl eshy lip, posterior part concave; dorsal plate small, weakly sclerotized. Ovipositor lobes relatively short (2 times as long as wide), with pointed apex, dorsal surface bearing numerous short and stout setae.

Bionomics
Biology unknown. The moths were caught in a light trap in grasslands near marshes.

Diagnosis
Easily separated from other species of the group by the large, plate-like juxta, with the base slightly fl attened, without sclerotization, with a long and widening neck, ending on each side in a rounded apex, on both sides tufted with small-sized hairs (Fig. 2E).

Description
The description of the external features of the holotype by Viette (1967) was accurate ( Fig. 6G-H).
MALE GENITALIA (Fig. 2E, M). (After Viette 1967) Additional description: juxta large, plate-like, base slightly fl attened, without sclerotization, with long and widening neck, ending on each side in rounded apex, on both sides tufted with small-sized hairs; aedeagus short, stout, not curved, with two lateral areas adorned with short setae; hand-shaped vesica with tuft of needle-shaped cornutus, pointed obliquely downward.

Diagnosis
Male easily separated from males of other species of the group by the broadly based, stout, strongly curved cornutus, pointed downward at a right angle (Fig. 2N); female easily separated from females of other species of the group by the small sclerotized area at the base of the ductus bursae and the weakly sclerotized antrum (Fig. 3D). Paratype GHANA: 1 ♂, same locality and date as allotype; 12 paratypes of both sexes were recorded in the original description; only one was found in BMNH.

Description
The descriptions of the external features of the male holotype and female allotype by Bowden (1956) were accurate. The male looks very similar to the female; however, the general colour of the fore wing is a little bit darker in the male than in the female (Fig. 7A-D).

Bionomics
Acrapex mediopuncta is a markedly forest species inhabiting open patches of grasses along forest roads. Larvae collected in Ghana were reported from P. purpureum, R. compressa, S. arundinaceum and S. megaphylla (Bowden 1956) (Table 3). The few larvae collected in Cameroon, the Democratic Republic of the Congo and the Republic of the Congo by our group were all from S. megaphylla; unfortunately, no pictures were taken before pupation. Larvae were collected at the bottom of young stems and were always solitary. Typically, plants exhibiting signs of infestation by A. mediopuncta larvae have a curled, brown, central leaf. No pupae were found in the stems, and therefore the borers probably pupate in the soil near exit holes.

Diagnosis
Female easily separated from females of other species of the group by the strongly curved and toothshaped ovipositor lobes (Fig. 3E).

Etymology
Named after the host-plant Miscanthus violaceus (K.Schum.) Pilg. in Uganda.  Antennae fuscous dorsally and ochreous ventrally, fi liform; fl agellum adorned dorsally with black scales, palpus fuscous, eyes black. Head and base of thorax black, thorax ochreous; legs fuscous suffused with white scales, ringed with white; abdomen fuscous, dorsally suffused with grey scales, black ventrally, suffused with grey scales. FORE WING. Ground colour dark ochreous, suffused with fuscous, black and white scales, more heavily along veins and costal area; reniform indicated by few white scales, surrounded by some black scales; irrorated ochreous median area extended on distal side to termen; longitudinal grey median fascia along lower external margin of cell, ending obliquely at apex, adorned with two black elongated spots between veins; veins below cell adorned with grey, white and black scales; fringe grey white, slightly suffused with fuscous. Underside of fore wing with ground colour grey white, suffused with fuscous and some brown scales, more heavily on costa and close to termen. HIND WING. Ground colour white, strongly suffused with fuscous scales; veins slightly irrorated with fuscous scales, costa and apex more heavily suffused with fuscous scales; fringe grey white, suffused with fuscous. Underside of hind wing grey-white, suffused with fuscous scales, but much more heavily on costa and apex; veins slightly irrorated with fuscous scales.

WINGSPAN. 22 mm (1 ♀).
FEMALE GENITALIA (Fig. 3E). Corpus bursae elongated ovoid and globular, without signa; ductus seminalis from base of bursae; ductus bursae about one third length of corpus bursae, not sclerotised on bursa side, widening and sclerotised on ostial side; antrum narrow, band-like, slightly sclerotised, leaning on back and adorned with very narrow and strongly sclerotised plate divided in two in the middle. Ovipositor lobes relatively short (2 times as long as wide), with dorsal surface bearing numerous short and stout setae, apex of each lobe strongly curved and tooth-shaped.

Bionomics
Larvae were collected at the bottom of stems of M. violaceus growing in grasslands near marshes (Table 3); as many Acrapex species, A. miscantha sp. nov. is a markedly hygrophilous species. Unfortunately, no pictures were taken before pupation.

Diagnosis
Male easily separated from males of other species of the group by the small rounded protuberance on each side of the apex of the juxta and by the small curved, hand-shaped vesica (Fig. 2G, O); female easily separated from females of other species of the group by the strongly sclerotized antrum, with a European Journal of Taxonomy 270: 1-36 (2017) 22 large, broad ventral plate, slightly bilobate, widening to the front, the anterior part shaped like a thin lip, the posterior part concave (Fig. 3F).

Material examined
Holotype DEMOCRATIC REPUBLIC OF THE CONGO: ♂, North Kivu, Ngesho, Sep. 1937, J. Ghesquière leg. (MRAC, gen. prep. Berio N 3755). Both sexes look similar; however, the general shape of the female fore wing is more elongated at the apex than in the male and fore wings are also paler in females; antennae ochreous, fi liform in female, slightly ciliate in male; fl agellum fuscous, adorned dorsally with black scales, palpus fuscous, eyes brown. Head and base of thorax fuscous, thorax ochreous; legs ochreous, ringed with white; abdomen fuscous, suffused with grey scales. FORE WING. Ground colour ochreous, suffused with fuscous, black and white scales, more heavily along veins and costal area; reniform indicated by few white scales, surrounded by some black scales; row of black elongated spots on veins in front of reniform; longitudinal fuscous median fascia along lower external margin of cell, ending obliquely at apex; veins below cell adorned with fuscous scales; row of black elongated spots between veins on margin; fringe white, slightly suffused with fuscous. Underside of fore wing with ground colour ochreous, strongly suffused with fuscous and some brown scales, more heavily on costa and close to termen. HIND WING. Ground colour white in female, white ochreous in male, suffused with fuscous scales; veins slightly irrorated with fuscous scales, costa and apex more heavily suffused with fuscous scales; fringe white, suffused with fuscous. Underside of hind wing white, suffused with fuscous scales, but much more heavily on costa and apex; veins slightly irrorated, with fuscous scales.

Bionomics
Biology unknown. The moths were caught in a light trap in grasslands near woodlands.

Distribution
Cameroon, the Democratic Republic of the Congo, Uganda and Zambia. Known from several localities at medium altitude between 1000 and 1200 m a.s.l. Moths were found in a mosaic of lowland rainforest and secondary grassland (Mosaic #11) and from a mosaic of Zambezian dry evergreen forest and wetter miombo woodland (Mosaic #21) (White 1983) (Fig. 4), belonging to the Congolian and to the Zambezian bioregion respectively (Linder et al. 2012) (Fig. 5).

Diagnosis
Female easily separated from females of other species of the group by the sclerotized, band-like ventral plate, strongly concave on the front (Fig. 3G).

Etymology
The species epithet refers to the close similarity of the wing pattern with that of A. mediopuncta (Bowden, 1956). Description (Fig. 8E-F) Antennae ochreous, fi liform; fl agellum ochreous, palpus ochreous, eyes black. Head and base of thorax brown, thorax ochreous; legs brown, suffused with ochreous scales, ringed with ochreous; abdomen ochreous, suffused with fuscous scales. FORE WING. Ground colour bright ochreous, suffused with dark ochreous and fuscous scales, more heavily between veins and on costal area; reniform indicated by few white scales, surrounded by some black scales; longitudinal brown median fascia along lower external margin of cell, ending obliquely at apex, adorned with two black elongated spots between veins; row of black elongated spots between veins on margin; fringe ochreous, suffused with brown. Underside of fore wing with ground colour ochreous, heavily suffused with fuscous and brown scales.

Holotype
HIND WING. Ground colour grey white, strongly suffused with fuscous scales, more heavily on costa and apex; veins slightly irrorated, with fuscous scales; fringe grey white, suffused with fuscous. Underside of hind wing grey white, suffused with fuscous scales, but much more heavily on costa and apex; veins slightly irrorated, with fuscous scales.

Bionomics
Acrapex simillima sp. nov. is a markedly forest species, inhabiting open patches of grasses along forest roads. Larvae were all collected at the bottom of young stems of S. megaphylla (Table 3) and were always solitary. Typically, plants exhibiting signs of infestation by A. simillima sp. nov. larvae have a curled, brown central leaf. One pupa was found in a stem; however, as in most species of Acrapex, most larvae probably pupate in the soil near exit holes.

Diagnosis
Male easily separated from males of other species of the group by the pointed apex of the uncus, the ridge-like, roundly pointed expansion of the coastal margin and by the aedeagus having no vesica (Fig. 2H, P); female easily separated from females of other species of the group by the ductus bursae, which are widening and sclerotised on the ostial side, and by the narrow, band-like, slightly sclerotised antrum (Fig. 3H).  . quadrata, Sankuru, Dimbelenge, 25 Nov. 1950, Dr M. Fontaine leg. (MRAC, adult;MCSN, genitalia, Berio, E prep N.3753). MALAWI: 1 ♀, Mt Mlanje, Nyasaland, 30 Jun. 1913, S.A. Neave leg. (BMNH 1914-171, Agrotidae genitalia slide No 13455 ♂♂, Mt Mlanje, Nyasaland, 26 Mar. 1913, S.A. Neave leg. (BMNH 1914; 1 ♂, Luchenya River, Mlanje, Nyasaland, 26 Mar. 1913, S.A. Neave leg. (BMNH 1914 Redescription (Fig. 8G-J) The sexes look similar; however, the general shape of the female fore wing is more elongated at the apex than in the male; antennae fuscous, fi liform in female and slightly ciliate in male; fl agellum fuscous, adorned with grey scales, palpus fuscous, suffused with grey scales, eyes fuscous brown. Head and base of thorax brown, thorax dark ochreous; legs brown, suffused with grey scales, ringed with grey; abdomen fuscous, suffused with grey scales. FORE WING. Ground colour dark ochreous, suffused with fuscous and black scales, more heavily along veins, termen and costal area; reniform indicated by few white scales, surrounded by some brown scales; row of black elongated spots on veins in front of reniform; longitudinal brown median fascia along lower external margin of cell, ending obliquely at apex; veins below cell adorned with fuscous brown and white scales; row of black elongated spots between veins on margin; fringe fuscous, slightly suffused with brown. Underside of fore wing with ground colour grey, suffused with fuscous scales, more heavily on costa and close to termen. HIND WING. Ground colour white in female, white ochreous in male, heavily suffused with fuscous scales in male; veins heavily irrorated, with fuscous scales, costa and apex more heavily suffused with fuscous scales; fringe grey, suffused with fuscous. Underside of hind wing grey, suffused with fuscous scales, but much more heavily on costa and apex; veins slightly irrorated, with fuscous scales.

Bionomics
Acrapex unicolora is a markedly hygrophilous species of banks of streams, rivers and marshes. Larvae were collected in Tanzania from A. gayanus, Chrysopogon zizanoides (L.) Roberty, Cymbopogon schoenanthus subsp. proximus (Hochst. ex A.Rich.) Maire & Weller, Cymbopogon pospischilii (K. Schum.) C.E.Hubb., Hyparrhenia diplandra (Hack.) Stapf and S. sphacelata (Schumach.) Moss (Table 3). Larvae were collected at the bottom of young stems and were always solitary. Typically, plants exhibiting signs of infestation by A. unicolora larvae have a curled, brown central leaf. No pupae were found in stems and therefore borers probably pupate in the soil near exit holes.

Distribution
Angola, the Democratic Republic of the Congo, Malawi, Nigeria, the Republic of the Congo, Tanzania, Zambia and Zimbabwe. Known from many localities from sea level to 2147 m a.s.l. Moths were found in a mosaic of lowland rain forest and secondary grassland (Mosaic #11A), a mosaic of Zambezian dry evergreen forest and wetter miombo woodland (Mosaic #21), wetter Zambezian miombo woodland (Mosaic no 25) and undifferentiated montane vegetation (Mosaic #19) (White 1983) (Fig. 4), belonging to the Congolian and to the Zambezian bioregion, respectively (Linder et al. 2012) (Fig. 5).

Remarks
It is worth highlighting that the records of Acrapex hemiphlebia by Janse (1939) correspond to specimens from a different species that is not yet described and related to Acrapex albivena Hampson, 1910.

Phylogenetic and molecular species delimitation analyses
Maximum likelihood analyses performed with IQ-TREE yielded a well-supported topology (49 of the 70 nodes supported by BV > 70%; see Fig. 10), especially when considering interspecifi c relationships (17 of the corresponding 18 nodes supported by BV > 70%). The only representative of A. mediopuncta (formerly P. mediopuncta) is recovered in a derived position among other members of the genus Acrapex. Members of the A. albivena species group are recovered as sister to the unicolora group (A. albivena, A. salmona, A. sporobola, A. syscia and A. yakoba), with a high support (BV of 96%), while the only representative of the stygiata species group (A. stygiata) is found as sister to both the albivena and unicolora group (BV of 100%).
Results of the PTP molecular species delimitation are congruent with the results of the morphological study. Interestingly, PTP analyses highlight the existence of a potential new species refered to as Acrapex sp. SECOG7537 (Fig. 10). This specimen corresponds to a unique larva collected in the Republic of the Congo on Pennisetum unisetum (Nees) Benth.

Discussion
The ten species treated here make up a morphologically homogeneous group; this contradicts the statement made by Tams & Bowden (1953) about the isolation of the genus Poecopa. Indeed, the male genitalia of A. mediopuncta show the typical male characteristics of the A. unicolora group, namely the short and broad valves, the coastal margin slightly broadened on the inner side and produced into a spine and the short and stout aedeagus with a hand-shaped vesica with needle-shaped cornutus. The synonymy of Poecopa with Acrapex at the generic level is also entirely supported by the results of the phylogenetic analyses, which recover A. mediopuncta in a derived position within the clade encompassing all A. unicolora representatives. Although the ten species revised and described here present a very similar wing pattern and colour, they are easily separated with both male and female genitalia; the vesica is the most useful character to identify the males and the ventral plate of the antrum allows a clear identifi cation of the different females. However the group is composed of two ecological sub-groups, with Fig. 10. Maximum likelihood tree resulting from the analysis of the combined dataset carried out with IQ-TREE. Support of major nodes is displayed as BV (only BV > 50% are shown). On the right, corresponding adult habitus (for species belonging to the A. unicolora species group) are also included for illustrative purposes. Results of PTP analyses are fi gured using coloured branches and vertical side bars. Putative molecular species clusters are indicated using transitions between blue-coloured branches to red-coloured branches (vertical bars are also informative).
A. mediopuncta and A. simillima sp. nov. as markedly forest species inhabiting open patches of grasses in Guineo-Congolian rain forests of the Congolian bioregion and all the other species markedly hygrophilous of banks of streams, rivers and marshes in Zambezian miombo woodland belonging to the Zambezian bioregion. While A. unicolora, A. kafula sp. nov. and A. parvaclara are recorded from East Africa to western areas of Central Africa, our results suggest restricted distributions for all six other species. Despite extensive surveys in more than 16 sub-Saharan countries, we did not collect any species of the A. unicolora group in the Southern or Somalian Bioregions (Linder et al. 2012).
We report here for the fi rst time a host-plant association of A. unicolora to different species of Andropogonae and to one Panicae, S. sphacelata, and of A. miscantha sp. nov. to another Andropogonae, M. violaceus. The potential new species collected in the Republic of the Congo was also reared from another species of Andropogoneae, Pennisetum unisetum. Although we did not record any host plant association for other species of the group, considering that the grasses of the miombo woodland are normally members of the Andropogonae (McClanahan & Young 1996), we can hypothetize that most of the species should be associated to species of that tribe. This is also consistent with the pattern of hostplant associations that were demonstrated for other species of Acrapex (the albivena and stygiata species groups), which were exclusively reared from Andropogoneae (Le ).
As all recorded Acrapex larvae, the four Acrapex species of the A. unicolora group collected in the fi eld as larvae came from host plants belonging to the Sesamia-like species as defi ned by Le Ru et al. (2006b). They are morphologically similar, with ground colour pinkish buff, without any markings. The feeding habits of the four species are similar, with the typical symptom of plant attack being death of the central tiller, often referred to as 'dead heart'. In addition, as for Acrapex spp. (Le ), we always found the larvae solitary in the stems. We speculate that Acrapex larvae typically fed on more than one stem before completing their development. We suspect that the larvae disperse when they reach the fourth instar. No pupae were found in stems, and therefore borers probably pupate in the soil.