Three new species of the Chinese planthopper genus Tetricodes Fennah (Hemiptera, Fulgoroidea, Issidae, Parahiraciini)

Abstract The diagnostic characters of the Chinese planthopper genus Tetricodes Fennah, 1956 are redefined. Three new species of this genus, T. ansatus Chang & Chen, sp. n. (China: Guangxi), T. parvispinus Chang & Chen, sp. n. (China: Guizhou) and T. similis Chang & Chen, sp. n. (China: Guizhou) are described and illustrated. The female genitalia of the genus is described and illustrated for the first time. A checklist and key to the species of Tetricodes are given. The synonymy of Tetricodes songae Zhang & Chen, 2009 with Tetricodes polyphemus Fennah, 1956, syn. n., is proposed.


Introduction
The planthopper tribe Parahiraciini Cheng & Yang, 1991 (Hemiptera: Issidae) is a relatively small tribe distributed mainly in the Oriental region but also occurring in the Palaearctic region . In recent years, some genera and species were added or moved into this tribe (Gnezdilov and Wilson 2005;Meng et al. 2015;Wang et al. 2015Wang et al. , 2016Gnezdilov and Hayashi 2016;Gnezdilov and Bourgoin 2016); to date, the tribe contains 19 genera and 68 species. Parahiraciini can be distinguished from other issid tribes by: body elongate ovate; forewings with claval suture; hindwings well developed, bilobed, and with a network of veins.
The genus Tetricodes was established by Fennah (1956) for T. polyphemus Fennah, 1956 as the type species from China (Hubei), with generic characters mainly based on a female specimen. Zhang and Chen (2009) transferred Tetricodes from the tribe Thioniini Melichar, 1906 to Parahiraciini and were first to recorded the male genitalia of the type species and one other species, T. songae from Guizhou, China. Subsequently, Chen et al. (2014) described another new species T. anlongensis. According to the frons with or without a light median line, Gnezdilov (2015) proposed that T. polyphemus in Zhang and Chen (2009) was a new species, T. fennahi Gnezdilov, 2015; up to date, the genus includes four species.
The main aim of this paper is to describe three new species of Tetricodes (Hemiptera: Issidae) from China (Guangxi, Guizhou), and propose a new species synonym. Also, type specimens are discussed, generic characteristics are redefined and a checklist and key to species of Tetricodes are provided.

Materials and methods
The morphological terminology of the head and body follows Chan and Yang (1994), and the terminology of male and female genitalia follows Bourgoin (1993) and Gnezdilov (2002Gnezdilov ( , 2003. Dry specimens were used for descriptions and illustrations. External morphology was observed under a stereoscopic microscope. All measurements are in millimeters (mm). The body measurements are from the apex of vertex to the tip of the forewing. The genital segments of the examined specimens were macerated in 10% KOH, washed in water and transferred to glycerine. Illustrations of the specimens were made with a Leica MZ 12.5 stereomicroscope. Photographs were taken with a KEYENCE VHX-1000C.
The type specimens of new and other species and other examined specimens are all deposited in the Institute of Entomology, Guizhou University, Guiyang, China (IEGU).
Coloration. General color brown, with irregular black mottling. Vertex with black speckles near base (Fig. 7). Eyes brown to black (Fig. 8). Frons ( Fig. 9) with small black protuberance with light median line running from the upper margin, with narrow pale transverse clearer band under the black protuberance, to nearly the basal 1/3 of face, not reaching ventrally level of compound eyes, and pale spots near lateral margins. Clypeus brown with pale marks in middle line and rostrum brown. Forewings ( Fig. 1) with irregular black mottling. Legs with tips of spines on hind tibiae and tarsi black.
Male genitalia. Anal tube (Fig. 13) irregularly pentagonal in dorsal view, the widest breath in apical 1/3. Anal style (Fig. 13) short, located at the base 1/3 of anal tube. Pygofer (Fig. 12) narrow and curved in lateral view, irregular sub-quadrate. Genital styles (Fig. 12) short, without triangular prominence near dorsal margin before capitulum; capitulum of genital styles relatively short, subtrapezoidal on short neck. Phallobase with dorsal lobe cystiform at apical part, with irregular lobes in apical 1/4 in lateral view (Fig. 14a), bean-shaped process in basal dorsal margin (Fig. 14b), with big ansate process (Fig. 14c) in subbasal dorsal margin in lateral view; lateral lobe splitting into two stout branches, with stout sub-angular processes near apical (Figs 14d, 15d) ; ventral lobe short, not reaching to the tip of dorsal lobe, in ventral view ventral lobe with three lobes near apical part (Figs 14e, 15e). Aedeagus with pair of small sheet-like processes at apical 1/3 in lateral view (Figs 14f, 15f ).
Etymology. The name is derived from the Latin noun "ansatus", meaning phallobase with big handle-shaped process in subbasal dorsal margin in lateral view.
Coloration. General color yellowish green, with irregularly black mottling (Fig.  3). Eyes yellow to brown (Fig. 23). Frons (Fig. 24) with medium black protuberance with light median line running from the upper margin, with broad pale transverse clearer band under the black protuberance to nearly the basal 1/2 of face, reaching or surpassing ventrally level of compund eyes, and pale spots near lateral margins. Clypeus brown with yellow mark in base and rostrum brown. Pronotum (Fig. 22) with three pale vurrucae betwwen median carina and lateral carina. Forewings (Fig. 3) with irregularly black mottling near margins.
Male genitalia. Anal tube (Fig. 28) irregular pentagonal in dorsal view, the apical margin truncated, the widest breath in apical 1/3. Anal style (Fig. 28) short, located in the middle of anal tube. Pygofer (Fig. 27) narrow and curved in lateral view, irregular subquadrate. Genital styles (Fig. 27) short, without triangular prominence near dorsal margin before capitulum; capitulum of genital styles relatively short, subtrapezoidal on short neck. Phallobase with dorsal lobe with irregular lobes (Fig. 29a) at apical part in lateral view, with small spine in dorsal margin of long lobe-shaped process in base (Fig.  29b); lateral lobe splitting into two stout branches, apical part subtriangular (Figs 29c, 30c); ventral lobe short, ventral view ventral lobe with three lobe near apical part, the apical lobe narrowed (Figs 29d, 30d). Aedeagus with pair of big sheet-like processes at apical 1/3 in lateral view (Figs 29e, 30e).
Etymology. This species epithet is derived from combination of Latin root prefix "parv-" and "spine", referring to the small spine in the dorsal margin of basal long process of aedeagus.
Host plant. Unknown. Distribution. China (Guizhou). Diagnosis. This species can be distinguished from other Tetricodes species by the anal tube (Fig. 37) irregular circular, with sunken trilateral at apical margin in dorsal view; phallobase with dorsal lobe with irregular collar-shaped and long lobe-shaped process (Fig. 38a); lateral lobe with a stout lobe-like prominence and hook-shaped prominence in apical part in ventral view (Fig. 39c). Aedeagus with big sheet-like processes in lateral view (Fig. 38e).
Male genitalia. Anal tube (Fig. 37) irregular circular, with pitted triangular in apical margin in dorsal view, the widest breath in apical 1/2. Anal style (Fig. 37) long, located in the middle of anal tube. Pygofer (Fig. 36) narrow and curved in lateral view, irregular subquadrate. Genital styles (Fig. 36) short, with obscure triangular prominence near dorsal margin before capitulum; capitulum of genital styles relatively short, subtrapezoidal on short neck. Phallobase with dorsal lobe with irregularly collar- shaped process near apical part in lateral view (Fig. 38a), with long lobe-shaped process in dorsal margin in base (Fig. 38b); lateral lobe splitting into two branches, with stout lobe-like prominence and hook-shaped prominence in apical part in ventral view (Figs 38c,39c); ventral lobe short, in ventral view ventral lobe with three lobe near apical part, the apical margin acute (Figs 38d, 39d). Aedeagus with pair of big sheet processes in apical 1/3 in lateral view (Figs 38e, 39e).
Etymology. This new species is named for its similarity to the above new species. Host plant. Unknown. Distribution. China (Guizhou).

Tetricodes polyphemus Fennah, 1956
Tetricodes polyphemus Fennah, 1956: 514. Tetricodes songae Zhang & Chen, 2009 :19, figs 11-19, 23-27 ;Chen et al. 2014: 120, figs 2-62. Distribution. China (Guizhou, Hubei, Hunan, Yunnan). Remarks. The above synonymy is based on examination of the type specimens (male and female) of Tetricodes songae (from Guizhou Province) and the specimens of T. polyphemus collected from the type locality (Hubei Province, 1 female) and Hunan Province (male and female). Although Hunan, to which the locality of collecting the male material of T. polyphemus belongs, is different from the type locality (Hubei), the distance between the above localities is very close. The male genitalia of T. songae and T. polyphemus are identical.

Discussion
The species of Tetricodes are very similar in colouration and external morphology. Based on black protuberance of frons without light median line, Gnezdilov (2015) considered that the species T. polyphemus treated by Zhang and Chen (2009) is another new