Bicaubittacus appendiculatus ( Esben-Petersen, 1927 ) Esben-Petersen, 1927

Tan, Jiang-Li & Hua, Bao-Zhen, 2009, Bicaubittacus, a new genus of the Oriental Bittacidae (Mecoptera) with descriptions of two new species, Zootaxa 2221, pp. 27-40 : 30-31

Bicaubittacus appendiculatus ( Esben-Petersen, 1927) , comb. nov.

( Figs 1–2 )

Bittacus appendiculatus Esben-Petersen, 1927: 14 , type locality: Yunnan, China. – Cheng, 1957: 106; – Byers, 1970: 383.

Diagnosi s. Bicaubittacus appendiculatus is similar to Bi. yangi sp. nov., but differs from the latter by the dorsal margin of epandrial appendage in male extending ventro-mesad into a large subtriangular lobe; gonostylus short, with upturned, truncate, flat and broad apex.

Redescription. Body 17 mm long. Forewing 18.5 mm long, 4.5 mm wide. Hindwing 16.1 mm long, 4.0 mm wide. Head with vertex and frons yellowish brown; rostrum, maxillary and labial palps dark brown. Antennae filiform, about 6.8 mm long; flagellum ciliated with about 21 flagellomeres. Compound eyes black; ocellar triangle black.

Pronotum unevenly dark brown; two long, black setae on anterior margin. Anterior two-thirds of mesonotum unevenly blackish brown with a pale brown median streak gradually wider posteriorly; metanotum blackish brown along both sides of prescutum, the remaining part pale. Pleura, coxae and mera light brown except a small black spot on the posterior margin of each coxa. Legs yellowish brown; femora and tibiae with dark apices; tarsi light brown, becoming progressively darker towards terminal segments; the two distal tibial spurs almost equal in length; fourth tarsomere with a spine on each side.

Wings ( Fig. 1 A) unspotted with dingy yellowish tint; distal margin of wing indistinctly diffused with brownish clouding; pterostigma prominent; nygmata yellowish brown; thyridium at FM. Forewing: Pcv 1 or 2; Av absent; Cuv ending slightly before the level of FM; vein 1A terminating far before FM; Sc ending close to the level of FRs; Subcostal radius crossveins (Scv) at about the middle of ORs and FRs. Hindwing similar to forewing, but Sc ending well before FRs; Scv near ORs.

Abdomen of male with terga II–VIII yellowish brown, each with a narrow black antecosta; posterior margin of terga VI–VIII deeply emarginate in V-shape; posterior angles of terga VI–VII blackish brown; sex pheromone glands between terga VI–VII and VII–VIII bilobed ( Fig. 2 A). Epandrial appendage complicated by an apical prolongation, a subtriangular hook-tipped ventral process, and large setiferous mesal lobe with a small patch of stout, curved spines above its base ( Figs 1 B, 2A, B). Gonocoxites bearing a pair of slender, weakly sclerotized, setiferous prolongations with sparse long black setae along the distal part; the apical three setae significantly long ( Figs 1 B, 2A); gonostylus irregular in shape, with a large mesal process subbasally, an upturned truncate apex, flat and broad ( Figs 1 B, 2A, 2C). The upper branch of proctiger long, with a dorsal subapical tuft of hairs; apex emarginated into two unequal processes, roughly L-shaped, dorsal (subapical) process rounded and broad, ventral (apical) one slender, tapering apically ( Figs 1 B, 2A). The aedeagus relatively small, with scoop-like penunci on each side at base; penisfilum coiled ( Fig. 2 C).

Abdomen of female with terga I–IX dingy yellow; posterior part of tergum VII and middle part of tergum VIII unevenly fuscous; terga III–IX each with narrow black antecosta. Subgenital plate irregular in shape, its dorsal margin slightly curved and not deeply emarginate ( Fig. 2 F); distal margin narrowly prolonged caudad; the two halves separated to the very apex by membrane ( Fig. 2 G). Tergum X pale, dingy yellow, extending very slightly ventrad; supraanale shallowly emarginate at apex, subanale truncate ( Figs 2 D, E). Material examined. 3 ɗ, 3 Ψ, CHINA: YUNNAN: Yangjiahe (alt. 1910 m), Hutiaoxia (Tiger Leaping Gorge, 27°09'37''N, 100°03'28''E) along the Jinsha River, Shangri-la (formerly Zhongdian Co.), 16.VI.2007, coll. Cai Lijun, preserved in the Entomological Museum, Northwest A&F University, Shaanxi [NWAU]. Distribution. China (Yunnan).

Remarks. This species previously was known only by the male holotype. The female is described and illustrated here for the first time.

Figures

FIGURE 1. Bicaubittacus appendiculatus. A. Male adult; B. Male genitalia, lateral view.

FIGURE 2. Bicaubittacus appendiculatus, genitalia. A – C. Male: A. Terminal abdominal segments, lateral view; B. Right epandrial appendage, mesal view; C. Aedeagus and gonostylus, lateral view. D – G. Female: D. Abdominal segment X, dorsal view; E. ibid, ventral view; F. Posterior abdominal segments, lateral view; G. Subgenital plate, ventral view.