A key to the genera of Issini ( Hemiptera : Fulgoromorpha : Issidae ) of China and neighbouring countries , with descriptions of a new genus and two new species

Abstract. A new genus in the tribe Issini (Hemiptera: Fulgoromorpha: Issidae) is described from South China: Orbita Meng & Wang, gen. nov., its type species Orbita parallelodroma Meng & Wang, gen. et sp. nov. (China: Fujian) is described and illustrated. In addition, one new species of Neokodaiana Yang, N. minensis sp. nov. is described and illustrated from the same locality as the new genus. A key to the genera of Issini from China and neighbouring countries is provided.


Introduction
The tribe Issini Spinola, 1839 is the largest group in the family Issidae, including 134 genera with 712 species distributed worldwide (Gnezdilov 2013a;Chen et al. 2014;Bourgoin 2015).This tribe can be diagnosed by the following characters: body ovate, head without proboscis on the frons and postclypeus, frontoclypeal suture arched or almost straight, pronotum with large disc and narrow lateral lobes, hind margin almost straight, tegmen usually not hemispherical, with distinct veins and claval suture, hind wing well-developed and very often also rudimentary, bi-or trilobed, and hind tibia usually with two lateral spines, sometimes without lateral spines.

Materials and methods
The external morphology was observed under a Leica MZ 125 microscope.All measurements are in millimeters (mm).The terminology used for the external morphology follows Chan & Yang (1994), the forewing venation pattern follows Bourgoin et al. (2014), "paradiscal fi elds of pronotum" follows Anufriev & Emeljanov (1988) and "hypocostal plate of fore wing" follows Emeljanov (1971).The terminology of the male genitalia follows Gnezdilov et al. (2014b), female genitalia mainly follows Bourgoin (1993).The genital segments of the examined specimens were dissected and boiled in 10% NaOH solution for about 2-3 minutes and subsequently transferred into glycerin.Photographs of the specimens were made using a Leica M205A microscope with a Leica DFC Camera.Images were produced using the software version LAS (Leica Application Suite) V3.7.Two females of Neokodaiana minensis Meng & Qin sp.nov.are deposited in the Entomological Museum of Northwest Agriculture and Forestry University (NWAFU), Yangling, China, and all other specimens were borrowed from the Department of Entomology, China Agricultural University (CAU).
The measurements were mainly taken after Constant (2004) and the following abbreviations are used:

Diagnoses for genera in the key
A short diagnosis for each genus, except for the new genus in the key, is provided below.We follow the defi nition of these genera from the original description, in combination with their respective redescriptions in the latest literature, which results in the following distinctive set of features: Celyphoma Emeljanov, 1971Celyphoma Emeljanov, 1971: 625 (type species: Celyphoma fruticulina Emeljanov, 1971, by original designation).

Diagnosis
The genus can be recognized by the following characters: small sized; vertex distinctly wider than long; frons elongate, with median carina, upper margin arcuate or slightly concave; mesonotum with inverted V or Y-shaped carina at middle; hind wing rudimentary; hind tibia with 1-2 lateral spines; phallobase with one or two pairs of lateral processes, aedeagus with pair of ventral processes.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex twice as wide as long medially, without median carina; frons wide, median carina not reaching frontoclypeal suture; tegmen elongate, with narrow hypocostal plate; Sc short, not reaching over middle; hind wing trilobed; hind margin of female sternum VII convex medially.

Diagnosis
The genus can be recognized by the following characters: medium to large-sized; vertex elongate, lateral margins keel-shaped; frons narrow, weakly enlarged above clypeus, with median carina; lower part of postclypeus and anteclypeus with median triangular projection; tegmen broad, without hypocostal plate; hind wing trilobed; each dorsolateral phallobase lobe with large, nearly triangular, serrated subapical process; aedeagus with pair of long acuminate ventral hooks.

Diagnosis
The genus can be recognized by the following characters: medium-sized; frons broad, median carina present in basal half, with a line of verrucae along lateral margin on each side; hindwing trilobed, vannus and anal lobe small; genital style with large long process at base of capitulum; dorsal lobe of phallobase membranaceous, aedeagus with two pairs of ventral processes.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex 1.6-2.0times wider than long; frons shortly ampliated, median and sublateral carinae distinct, reaching over middle, sublateral carinae cross median carina below apical margin of vertex; tegmen elongate, Sc long, reaching over middle; phallobase with lateral lobes pigmented, usually short; aedeagus with a pair of processes, directed cephalad.

Diagnosis
The genus can be recognized by the following characters: medium-sized, body hemispherical; vertex three times wider than long; frons slightly wider than long, median carina present in basal half; postclypeus right angulate in lateral view; tegmen with longitudinal veins indistinct, densely reticulate, clavus reaching over middle of tegmen; hind wing tiny.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex about three times wider than long; frons longer than broad, disc fi nely granulate, with a row of submarginal pustules laterally on each side; postclypeus roundly curved in lateral view; tegmen with claval suture distinct, claval veins uniting distad of middle of clavus; hind wing more than half length of tegmen, veins reticulate.

Diagnosis
The genus can be recognized by the following characters: medium to large-sized; vertex wider than long, anterior margin rounded; frons as long in middle line as wide at widest part, median carina distinct, median and transverse sublateral carinae joined below vertex; hind wing trilobed, veins reticulate, anal lobe rudimentary; fi rst metatarsomere with more than 35 intermediate spines; suspensorium large, nearly reaching to the apex of phallobase, phallobase at base angulately convex on ventral side.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex a little longer than wide, anterior margin angularly produced; frons as long in middle line as wide at widest part, median carina indistinct; tegmen elongate, Sc long, reaching over middle; hind wing well-developed.

Diagnosis
The genus can be recognized by the following characters: medium-sized, body smooth and shiny, hemispherical; vertex 2.5-2.7 times wider than long; frons long, with median carina; clypeus convex centrally, sloped at basal one third; tegmen hemispherical, claval suture present; hind wing rudimentary, less than half length of tegmen, veins simple.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex three times wider than long in midline; frons more than 2.0 times wider than long, median carina feeble, sublateral carinae far below anterior margin of vertex, disc convex; hind wings trilobed, vannus and anal lobe reduced; aedeagus with lateral phallobasal lobes dentate dorsally near apex, with large lobe-like processes laterally and a pair of hooks ventrally.

Diagnosis
The genus can be recognized by the following characters: medium to large-sized; vertex twice as wide as long; frons shortly amplicated, median carina reaching to middle, sublateral carina feeble; tegmen elongate, Sc not reaching over middle, MP forked near middle; hind wing trilobed; aedeagus with two pairs of ventral processes, dosal one short, ventral one long.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex distinctly wider than long, median carina feeble; frons with median carinae and sublateral carinae present at upper half; tegmen with Sc long and reaching over middle; hind wing trilobed.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex more than three times longer than wide, apex upcurved; pronotum and mesonotum without median and sublateral carinae; tegmen thickly and coarsely reticulate, claval suture present; hind wing trilobed, veins reticulate, anal lobe rudimentary.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex transverse, median carina sometimes weak; frons wide, with median carina, sublateral carinae distinct only in upper half; tegmen with hypocostal plate; Sc short and fusing with R forming a loop; hind wing well three-lobed.

Diagnosis
The genus can be recognized by the following characters: medium to large-sized; vertex slightly wider than long, with weak median carina; frons with a row of submarginal tubercules on each side, median carina short, sublateral carina indistinct; tegmen without hypocostal plate, Sc just reaching midlength of tegmen, MP forked near distal one-third of tegmen; hind wing trilobed; phallobase with dorsolateral lobe bearing a pair of strong processes apically; aedeagus with a pair of long hooks at middle.

Diagnosis
The genus can be recognized by the following characters: medium to large-sized; vertex 1.7 times wider than long, anterior margin evenly angulate; frons shortly ampliated, median carina distinct at basal third, submedian carina only distinct transversely; tegmen elongate, Sc not reaching over middle; hind wing trilobed.

Diagnosis
The genus can be recognized by the following characters: medium-sized; frons elongate and wholly visible from above, sublateral carinae absent, frons and vertex joined at obtuse angle; postclypeus large, in shape of fl attened laterally proboscis bearing a median carina, resembling a chisel; tegmen with reticulate venation and without hypocostal plate; hind wing one-lobed; hind tibia distally with a single lateral spine.

Diagnosis
The genus can be recognized by the following characters: medium-sized; vertex transverse, with median carina; frons with strong median carina which runs through it, continued through the clypeus; tegmen with wide hypocostal plate; hind wing well-developed, trilobed.The new genus differs from Yangissus in the following combination of characters (features of Yangissus in parentheses): 1) frons with distinct median carina reaching to below eyes, without sublateral carinae, lateral margin auricularly extended below antennae (frons with feeble median carina almost reaching to frontoclypeal suture, with feeble sublateral carinae, lateral margin obtusely extended below antennae); 2) hind wing without transverse veins between CuP and Pcu (hindwing with transverse veins between CuP and Pcu); 3) pygofer with hind margin oblique and weakly convex at ventral half, caudo-dorsal angle blunt not protudent (pygofer with hind margin slightly convex medially, caudo-dorsal angle triangularly protrudent); 4) lateral lobe of phallobase becoming into processes at basal one third (lateral lobe bearing processes near apex).

Etymology
The generic name is derived from the orbs on the frons.The name is feminine in gender.
THORAX.Pronotum almost as long as vertex in middle line, anterior margin strongly convex between eyes, posterior margin emarginate medially, median carina weak, disc smooth without any tubercula and with two pits in middle area (Fig. 4A), paradiscal fi elds very thin and narrow behind eyes, lateral lobes wide, lamelliform, without any ridge, ventral margin moderately oblique (Fig. 4C).Mesonotum triangular, slightly shorter than length of pronotum and vertex together; anterior margin almost straight and slightly convex at middle; with three feeble carinae (Fig. 4A).
TEGMEN.Elongate, without hypocostal plate (Fig. 4D, see the arrow); basal surface strongly elevated near costal margin, apical margin rounded; inner margin straight, postcostal area much broader than costal area, with 2-3 transverse veinlets; veins ScP+R, MP and CuA separated at base; veins ScP+R forking close to basal cell; ScP not reaching beyond midlength of tegmen, very weak near costal margin; R simple, forked near apex, MP and CuA both forked almost at same level and slightly beyond the union of claval veins, MP 1 +MP 2 forked near apex, MP 1 and MP 2 respectively biforked just before apex, longitudinal veins distinctly prominent and transverse veins relatively weak.Clavus long, almost reaching apex, two claval veins (Pcu and A1) united at middle of clavus (Fig. 4E).
HIND WING.Well developed, trilobed.Veins R and CuA each with two branches near distal part; M fused with CuA near base; A1 separated at base with posterior branch slightly weakened in comparison with the anterior branch at apex; Pcu and A1 fused in their middle section and subsequently diverging in apical part; M, CuP, A 2 simple, between R2 and M and between M and CuA1 with single transverse vein (R 2 r-m M 1 m-cu CuA 2 CuP 1 Pcu 1 A 1 2 A 2 1); CuA2 and CuP fused and thickened at apex (Fig. 4F).
LEGS.Fore and median femora slightly dorso-ventrally fl attened; fore and median tibiae thin; hind tibia with two or three lateral spines.
MALE GENITALIA.Anal tube elongate, widest at base; lateral margin subparallel, apical margin rounded; slightly arcuately bent down near middle in lateral view; anal column very short, situated at base (Fig. 5A).Pygofer with hind margin strongly concave medially, caudo-dorsal angle blunt (Fig. 5B).Penis shallowly curved; dorso-lateral phallobase lobes separated into dorsal lobe and lateral lobe, lateral lobe fused with dorsal lobe shortly at basal one third, before and after the fused part, lateral lobe turned into a process directing cephalad and one more process directing caudad; aedeagus without ventral hooks, with a small lateral process at basal one-third (Fig. 5D-F).Genital style in lateral view with hind margin distinctly excavated at middle (Fig. 5B).
SIZE.Size of the single species hitherto recorded ranges from 5.8 to 5.9 mm of males, 6.2 to 6.4 mm of females.

Etymology
The specifi c epithet is constituted from the ancient Greek words "parallelos" meaning parallel and "dromos" meaning running, refers to the pair of long spiniform processes of phallobasal lateral lobe directing caudad parallel to each other.

Description
BODY. Brown alternated with yellow green and fuscous.
THORAX.Pronotum fulvous with yellowish green median line, two fuscous pits in middle, lateral lobes brown.Mesonotum dark brown, with median line and anterior angles green; lateral area with fuscous speckles (Fig. 4A).
LEGS.Fore and median femora fulvous with fuscous longitudinal fascia laterally and transverse stripe apically; fore and median tibiae fulvous with fuscous transverse stripes respectively at base and apex; hind femur fulvous with fuscous fascia at apex, hind tibiae fulvous, tips of teeth black.Metatibiotarsal formula 2-3+8/8/2.ABDOMEN.Dark brown.MALE GENITALIA.Dorsal phallobase lobe with a short process at apical one-third of lateral margin; lateral lobe turned into a long spiniform process directing caudad and a thick unciform process directing cephalad with apex curved caudad at basal third; ventral lobe narrow and long, weakly wide at middle and narrowing to obtuse and membranous apex; apical margin concave medially (Fig. 5D-E).Genital style in lateral view with hind margin distinctly excavated at middle (Fig. 5B).Capitulum of style narrowing to obtuse apex directing cephalad with a small blunt tooth in lateral view; in caudal view, lateral teeth thin and falcate (Fig. 5B-C).FEMALE GENITALIA.Gonoplac with apical margin strongly convex at dorsal half; disc elevated near base in dorsal view; fork well pigmented (Fig. 5J-K).Proximal part of posterior connective lamina of gonapophyses IX slightly convex in lateral view; median fi eld bifurcate at apex in dorsal view (Fig. 5G-H).Endogonocoxal process foliate; apex obtuse with thin setae (Fig. 5M); endogonocoxal lobe moderately long and weakly concave inward, well sclerotized (Fig. 5M).Anterior connective laminae of gonapophysis VIII broad; ventral margin straight, bearing small obtuse tooth near subapex and then concave to apex; apical group with three small teeth, and bearing a tiny tooth in opposite direction of the three teeth; lateral group with fi ve keeled teeth (Fig. 5M).Sternum VII with apical margin distinctly arcuately convex at middle (Fig. 5L).

Note
The monotypical genus Neokodaiana was erected for Neokodaiana chihpenensis from Taiwan by Yang in Chan & Yang (1994).It can be diagnosed by the unique distinctly wide frons (mentioned in the key above); tegmen with wide hypocostal plate; lateral phallobasal lobes well-developed showing dorsal margin dentate near apex, with large lobe-like processes directed caudad before it; in ventral view, bearing a pair of hooks; genital style with hind margin bowl-shaped concave and apicoventral angle quadrate convex.

Diagnosis
This new species resembles N. chihpenensis Yang, 1994, but can be distinguished by the following combination of characters (features of N. chihpenensis in parentheses): 1) anal tube with large triangular projection near apex in lateral view (anal tube with the lateral projection small near apex); 2) lateral phallobasal lobes with the middle triangular lobe-like processes long, anterior margin not dentate (anterior margin of the processes dentate); 3) the ventral hooks of phallobasal lobes short (the ventral hooks long, reaching nearly to apex); 4) sternite VII with posterior margin strongly widely convex at middle part (in N. chihpenensis, sternite VII with posterior margin slightly produced, truncate and curved at apex).

Etymology
The specifi c epithet refers to the type locality, Min, an alternative term for Fujian Province in China.
LEGS.Fore and median femora slightly dorso-ventrally fl attened, fuscous, and yellow basally; fore and median tibiae dark brown with yellow at base; hind femur and tibia fulvous, margins fuscous, and tips of teeth black.Metatibiotarsal formula 2+12/12, 15/2.ABDOMEN.Fulvous.MALE GENITALIA.Anal tube gradually widening to subapex; apical margin obtusely convex, and emarginate in middle; in profi le, subapex with large triangular projection; column moderately long, placed at middle (Fig. 6E, H).Pygofer roundly convex at posterodorsal angle, narrowing to ventral margin (Fig. 6E).Connective strongly sclerotized, very thick and large at base (Fig. 6I).Lateral phallobasal lobes elongated and enlarged at apex; dorsal margin dentate near apex, with triangular lobe-like processes large; in ventral view, bearing a pair of short hooks, directed laterally; ventral lobe sclerotized, with apical margin blunt and curved dorsally (Figs 6J, 7C-D).Genital style relatively wide and quadrate; apical margin with deep bowl-shaped concavity below capitulum of style; dorsal margin oblique and roundly convex in middle; ventral margin moderately straight; apicoventral angle quadrate convex (Fig. 6G).Capitulum of style short, apex obtuse and spinal outside, with relatively small lateral tooth (Fig. 6F).FEMALE GENITALIA.Anal tube subrectangular in dorsal view, lateral margin subparallel, narrowing down near straight apical margin; column situated near base (Fig. 8A).Gonoplacs in profi le slightly longer than wide; apical margin obtuse and membranous; in dorsal view, disc strongly elevated at basal half; fork well-sclerotized and pigmented (Fig. 8B-C).Posterior connective lamina of gonapophyses IX narrow and long, strongly convex at proximal part; median fi eld small and single; lateral fi eld with a pair of large teeth at level of apical margin of median fi eld (Fig. 8D-E).Gonospiculum bridge moderately long, with basal part shorter than apical part (Fig. 8E).Anterior connective laminae of gonapophysis VIII with three very small teeth grouped apically, fi ve small keeled grouped teeth on side (Fig. 8G).Sternite VII with posterior margin strongly widely convex at middle part (Fig. 8F).

Discussion
O. parallelodroma gen.et sp.nov.from southern China has two glossy rounded orbs on the frons, which are also present in Chlamydopteryx mammoides Gnezdilov & Fletcher, 2010from Queensland, Australia (Gnezdilov & Fletcher 2010) and in Redarator bimaculatus Distant, 1916 from South India (Distant 1916).The presence of this special feature in these three species from different geographical locations indicates a parallel evolution.The presence of two orbs might reveal a function similar to that suggested by Constant (2005: 62) for the smooth prominences on frons of Gelastopsis insignis Kirkaldy (Hemiptera: Fulgoromorpha: Eurybrachidae) as being mimicry of the large frontal eyes of salticid spiders.Many of these spiders are of similar size to these insects and move with short jumps.
DiagnosisThe genus can be recognized by the following characters: small to medium-sized; vertex transverse, nearly twice as wide as long medially; frons wide, with median carina distinct only, not reaching frontoclypeal suture; hind wing trilobed, with vannus and anal lobe rudimentary; genital style with a round process under capitulum; phallobase with pair of subapical processes laterally, aedeagus with a pair of ventral hooks.NeohemisphaeriusChen, Zhang & Chang, 2014 Neohemisphaerius Chen, Zhang & Chang, 2014: 80 (type species: Neohemisphaerius wugangensis Chen, Zhang & Chang, 2014, by original designation).