Indosialis Lestage

Liu, Xingyue, Yang, Ding & Hayashi, Fumio, 2006, Discovery of Indosialis from China, with description of one new species (Megaloptera: Sialidae), Zootaxa 1300, pp. 31-35 : 32

Genus Indosialis Lestage

Indosialis Lestage 1927: 118 . Type species: Protosialis minora Banks, 1920: 325 , by monotypy.

General characters. Small sized (forewing length 8–9 mm). Body yellowish or orange except for abdomen much darker. Wings grayish brown.

Head subquadrate, smooth and subshining, without raised scars. Male compound eyes distinctly prominent. Antennae filiform, scape distinctly inflated, pedicel shortened. Clypeal margin slightly prominent medially. Labrum suboval with anterior margin slightly incised.

Prothorax rectangular, twice as wide as long; meso­ and metathorax slightly wider than prothorax. Wings suboval; forewing about thrice as long as wide, with costal region feebly dilated. Costal region with basal cross veins distinct but with apical cross veins nearly lacking; R 2 + 3 2 ­branched, R 4 + 5 2 ­branched; 3 cross veins between R 1 and Rs; M 1 + 2 and M 3 + 4 simple.

Male ninth sternite broad, posteriorly produced more or less; male tenth tergite short, paired, subtriangular, with inner portion connected by membrane; male ninth gonostylus robust with rounded tip; male tenth sternite strongly sclerotized, with base expanded as wide plate, and with distal half divided into pair of elongate spinous lobes.

Female unknown.

Distribution. The genus is distributed only in Yunnan Province of China and Singapore.

Remarks. Indosialis appears to be closely related to Protosialis in having the similar orange body coloration, the distinctly prominent compound eyes of the male, the feebly dilated costal area, and the bifurcated R 2 + 3 and R 4 + 5, but can be easily separated from Protosialis by the simple M 3 + 4. In Protosialis , the M 3 + 4 is bifurcate. Furthermore, this genus also somewhat resembles the fossil genus Eosialis in having the similar venation, but the shape of the wings is suboval, which is distinctly different from the narrow elongate wings of Eosialis ( Nel et al. 2002).