Dilar taiwanensis Banks, 1937

Zhang, Wei, Liu, Xingyue, Aspoeck, Horst, Winterton, Shaun L. & Aspoeck, Ulrike, 2014, Species of the pleasing lacewing genus Dilar Rambur (Neuroptera, Dilaridae) from islands of East Asia, Deutsche Entomologische Zeitschrift 61 (2), pp. 141-153 : 143-145

Taxon classification Animalia Neuroptera Dilaridae

Dilar taiwanensis Banks, 1937 Figs 3, 17-20

Dilar taiwanensis Banks, 1937: 276. Type locality: China (Taiwan: Jiayi).

Dilar distinctus Nakahara, 1955b: 139. Type locality: China (Taiwan: Tattaka). syn. n.

Nepal kanoi Nakahara, 1955a: 6. Type locality: China (Taiwan: Tattaka). syn. n.

Diagnosis.

This species is characterized by the male ninth gonocoxite with anterior half broadly spoon-shaped and with posterior half slenderly elongate and curved posteroventrally, and by the slenderly elongate tenth gonocoxite which has a lobe connecting to ninth gonocoxite medially.

Description.

Male. Body length 3.4-5.5 mm; forewing length 6.4-9.0 mm, hindwing length 5.5-7.6 mm.

Head yellowish brown, with pale yellow setose tubercles. Compound eyes blackish brown. Antenna with ca. 29 segments, pale 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 eight flagellomeres simple.

Prothorax pale yellowish brown, pronotum yellowish brown, with anterior margin and posterolateral corners pale yellow, medially with a pair of ovoid markings; mesothorax pale yellowish brown, mesonotum dark brown on anterior and lateral margins; metanotum pale yellowish brown, slight darker on lateral margins. Legs pale yellowish brown, femora blackish brown at tip. Wings hyaline, slightly yellowish brown, with numerous dark spots. Forewing ~2.2 times as long as wide, densely spotted, with markings on proximal half much darker, most markings fused with each other, generally arranging into several arcuate transverse stripes, an immaculate area present distal to median nygma; two nygmata present on proximal and median portion of forewing, median one much larger than proximal one. Hindwing ~2.1 times as long as wide, slightly paler than forewing, with similar marking pattern; one nygma present at middle. Veins pale brown. Forewing with trichosors present along wing margin between R and CuP; Rs with four main branches; MP with two main branches; two gradate crossveins present at middle. Hindwing with trichosors present along wing margin between R and CuA; Rs with three main branches.

Abdomen pale yellowish brown, pregenital segments dorsally brown. Ninth tergite in dorsal view with an arcuate anterior incision and a nearly V-shaped posterior incision, leaving a narrow median portion and a pair of subtriangular hemitergites, which are obtuse distally and densely haired; in lateral view broad, with straight ventral margin and arcuate posterior margin. Ninth sternite obviously shorter than ninth tergite, arcuately convex posteriad. Ectoproct in dorsal view with a strong sclerotized projection medially, which is bifid at tip, posteroventrally with a pair of short and flattened projections, a pair of bifid unguiform projections and a pair of short, feebly sclerotized, digitiform projections. Ninth gonocoxite strongly inflated and spoon-shaped on anterior half, with posterior half slenderly elongate and curved posteroventrally, which is with a slenderly short projection extended subterminally; tenth gonocoxite slenderly elongate, much longer than ninth gonocoxite, with incurved base and spinous tip which is curved outward, medially with a lobe connecting to ninth gonocoxite; gonarcus beam-shaped, bifid on both ends, laterally connecting to base of ninth gonocoxites. Hypandrium internum nearly trapezoidal, with lateral margins slightly arcuate.

Female. Forewing length 12.5 mm, hindwing length 11.5 mm.

Abdomen yellow, ovipositor yellowish brown, seventh sternite ruptured during maceration, eighth abdominal segment without subgenitale. Colleterial gland apparently also ruptured, not visible. Bursa copulatrix sac-like in lateral view, with an elongated bowl-like sclerite and a paired sclerotized domed structure distally behind it; bursal accessory gland not observed. Ectoproct rather small, ovoid.

Materials examined.

Holotype ♂, "Formosa, Arizan [= Mt. Alishan, Taiwan, 23°31'N, 120°48'E], June 4, Gressitt, Type, M.C.Z. No. 20229" (MCZ). CHINA: 2♂, Taiwan, Taoyuan, Mt. Tamanshan [24°42'N, 121°27'E], 1600 m, 11.VI.2013, Feiyang Liang (CAU); 1♂, Taiwan, Taipei, Mt. Yangmingshan, Datun Park [25°09'N, 121°32'E], 900 m, 17.VI.2012, Lihua Wang (CAU); 2♂, Taiwan, Taipei, Mt. Yangmingshan, Datun Park, 900 m, 17.VI.2012, Luxi Liu (CAU); 5♂1f#, Taiwan, Nantou, Tayuling [23°55'N, 120°40'E], 2500 m, 8-18.VI.1998, D. R. Davis (NMNH); 1♂, "Formosa, Taihorin [Taiwan: Chiayi County, Dalin (= Taihorin), 23°35'N, 120°28'E], VI.10. [= June 1910], H. Sauter" (MNB); 2♂ [Holotype and a paratype of Dilar distinctus ], "Formosa, T. Kano/ Dilar distinctus n.sp. (Type) W. NAKAHARA/Waro Nakahara Collection II" (NSMT); 1♂ [Holotype of Dilar kanoi ], "Formosa, T. Kano/ Dilar kanoi n.sp. (Type) W. NAKAHARA/Waro Nakahara Collection II/NSMT-I-Nr No. 4340" (NSMT); 1♂, CHINA: Taiwan, 29.VII.1928, T. Kano (NSMT); JAPAN: 1♂, Iriomote Island, Upper Nakara River [24°20'N, 123°49'E], 12.III.1964, Y. Miyatake (NSMT).

Distribution.

China (Taiwan), Japan (Iriomote Island).

Remarks.

This species was originally described by Banks (1937) based on external morphology only. After our examination of the holotype of this species, we found that this species is identical with Dilar distinctus Nakahara and Dilar kanoi Nakahara based on the comparison of its male genitalia with the original genitalic illustrations of the latter two species. Therefore, we treat Dilar distinctus and Dilar kanoi as junior synonyms of D. taiwanensis. Nevertheless, it should be noted that the collecting labels of the primary types of Dilar distinctus and Dilar kanoi lack the information of the precise data of the collecting sites and dates, which however were indicated in the original descriptions ( Nakahara 1955a, b).

It is interesting that this species is polymorphic. Some individuals (See Figs 28, 30) have dark wings, while some individuals (See Figs 29, 31) have much paler wings. Therefore, it is difficult to identify the Taiwanese Dilar species only based on external morphology because of its significant intraspecific variations. Possibly, Dilar formosanus and Dilar pallidus are individual variations of Dilar taiwanensis , which, however, needs further clarification.

Considering the distribution, this species is firstly recorded in Iriomote Island, which is the southernmost island of Ryukyus, Japan.