Dilar geometroides Aspöck & Aspöck

Zhang, Wei, Liu, Xingyue, Aspöck, Horst & Aspöck, Ulrike, 2014, Revision of Chinese Dilaridae (Insecta: Neuroptera) (Part II): Species of the genus Dilar Rambur from Tibet, Zootaxa 3878 (6), pp. 551-562 : 553-555

Dilar geometroides Aspöck & Aspöck

( Figs. 1 , 4–7 , 16, 17 )

Dilar geometroides Aspöck & Aspöck, 1968: 15 . Type locality: Nepal (Janakpur). Dilar aspersus Yang, 1988: 197 . Type locality: China (Tibet: Linzhi). syn. nov.

Diagnosis. This species is characterized by the forewings with numerous pale brown markings, and the male complexes of gonocoxites 9, 10, and 11 with rather inflated ninth gonocoxites and slenderly elongate tenth gonocoxites, which are bifid at tip.

Description (Based on the larger specimens; see remarks). Male. Body length 4.0–7.0 mm; forewing length 10.0–12.0 mm, hindwing length 8.0–10.0 mm.

Head brown, with pale yellow setose tubercles. Compound eyes blackish brown. Antenna with ca. 28 segments, yellowish brown, pedicel with brown annular stripes, flagellum unipectinate on most flagellomeres, medial branches much longer than those on both ends, longest branch nearly 3.0 times as long as relevant flagellomere, but branch of 1st flagellomere short and dentate, distal seven flagellomeres simple.

Prothorax pale yellowish brown, pronotum brown, with anterior margin and posterolateral corners yellow, medially with a pair of ovoid markings; mesothorax pale yellowish brown, mesonotum dark brown on anterior and lateral margins; metanotum pale yellowish brown, slightly darker on lateral margins. Legs brown, femora blackish brown at tip. Wings hyaline, slightly smoky brown. Forewing ~2.4 times as long as wide, with numerous pale brown spots, arranging irregularly, proximal spots slightly darker, an immaculate area present distal to median nygma; two nygmata present on proximal and median portion of forewing ( Fig. 1 ). Hindwing ~2.2 times as long as wide, much paler than forewing; one nygma present at middle. Veins pale brown. Forewing with trichosors present along wing margin between R and CuA; costal crossveins simple, but occasionally forked; Sc just touching R in pterostigmatic region, terminally leaving several weak veinlets; Rs with four main branches; MA fused with R at wing base, proximally with no crossvein connecting to MP; MP with two main branches; two gradate crossveins present at middle. Hindwing with trichosors present along wing margin between R and CuA; Rs with four main branches.

Abdomen yellowish brown, pregenital segments dorsally dark brown. Ninth tergite in dorsal view with an arcuate anterior incision, a nearly U-shaped posterior incision and an elongate dorsoprocessus, leaving a pair of broad hemitergites, which are obtuse distally and densely haired ( Fig. 4 ); in lateral view broad, with straight ventral margin and arcuate posterior margin ( Fig. 6 ). Ninth sternite well-developed, slightly shorter than ninth tergite, arcuately convex posteriad in ventral view ( Fig. 5 ). Ectoproct in dorsal view with a shallowly arcuate anterior incision, posterodorsally with a pair of ventrally curved unguiform projections and a shallowly arcuate anterior incision, posteroventrally with a pair of nearly ovoid flattened projections, a pair of bifid unguiform projections and a feebly sclerotized, digitiform projection ( Fig. 4 ). Ninth gonocoxites inflated, nearly oblong, in dorsal view with unguiform tip; tenth gonocoxites slenderly elongate, incurved, with bifid unguiform tip, submedially with a lobe connecting to ninth gonocoxite; eleventh gonocoxites (= gonarcus) slenderly beam-shaped in dorsal view ( Fig. 4 ), laterally connecting to bases of ninth gonocoxites. Hypandrium internum nearly trapezoidal, with lateral margins slightly arcuate ( Fig. 5 ).

Female. Unknown.

Materials examined. 12♂ (Paratypes of D. aspersus ), CHINA: Tibet, Linzhi [29°39′N, 94°21′E], 3050 m, 8.VI.1978, Fasheng Li ( CAU); 1♂, CHINA: Tibet, Naidong [29°13′N, 91°45′E], 3553 m, 19.VI.1981, Tailu Chen ( CAU); 1♂, NEPAL: Terhathum, Phalambung [a locality of Kosi State, 27°11′N, 87°30′E], 1760 m, 25.IV.1962, T. Yasuda ( NSMT).

Material previously studied (i.e. type material of original description ( Aspöck & Aspöck 1968): 28♂, NEPAL, Sete [ca. 27°35′N 86°28′E], 2500–3500 m and Tampa Khosi valley [ca. 27°38′N 86°27′E], 2600 m (majority of the specimens in ZSM, partly in HUAC).

Distribution. China (Tibet) (new country record), Nepal (Janakpur, Kosi).

Remarks. This species was previously recorded only from Nepal ( Aspöck & Aspöck 1968). It appears to be closely related to Dilar tibetanus Yang by the similar male gonocoxite complexes 9, 10 and 11 with inflated, nearly oblong ninth gonocoxites, but it can be easily separated from D. tibetanus by the much paler forewings and the male gonocoxites complexes 9, 10, and 11 with slenderly elongate tenth gonocoxites, which is bifid at tip. In D. tibetanus , the tenth gonocoxites are spindled anteriorly and posteriorly, with median portion inflated.

D. geometroides shows a remarkable variability, which is characterized by large-sized dark specimens with forewing length 10–12 mm on one hand and small-sized pale specimens with forewing length 7–8 mm on the other hand ( Figs. 16 and 17 ). The Chinese specimens apparently have much narrower forewings than those from Nepal. The variability of the genital sclerites of the males is hardly commensurable quantitatively due to their complexity. The presently available material does not allow to differentiate whether it reflects a clinal phenomenon, polymorphism or character displacement.

Dilar aspersus Yang was originally described in a revision of Neuroptera from Tibet by Yang (1988) based on only external morphology, e.g. the marking pattern of mesothorax and the dense small spots on forewings. However, after examining the holotype of D. aspersus and several specimens of D. geometroides from Nepal, we found that the male genitalia of D. aspersus is the same as D. geometroides . Therefore, we treat D. aspersus as a junior synonym of D. geometroides .

Figures

FIGURES 1 – 3. Adults of Dilar spp. 1. D. geometroides Aspöck & Aspöck, male from Tibet; 2. D. harmandi (Navás), male from Tibet; 3. D. tibetanus Yang, male holotype. Scale bars: 1.0 mm.

FIGURES 4 – 7. Dilar geometroides Aspöck & Aspöck. 4. Male genitalia, dorsal view; 5. Male genitalia, ventral view; 6. Male genitalia, lateral view; 7. Male ectoproct, caudal view. e: ectoproct; g: gonarcus = eleventh gonocoxites; gx 9: ninth gonocoxite; gx 10: tenth gonocoxite; hi: hypandrium internum; S 9: sternite 9; T 9: tergite 9. Scale bars: 0.5 mm.

FIGURES 16 – 19. Individual variations of Dilar spp. 16. D. geometroides Aspöck & Aspöck, small-sized male from Nepal; 17. same species, large-sized male from Nepal; 18. D. harmandi (Navás), large-sized male from Nepal with dark wings; 19. same species, small-sized male from Nepal with bright wings. Scale bars: 1.0 mm.