Ilyobius Enderlein

Liu, Xingyue, Hayashi, Fumio & Yang, Ding, 2015, Taxonomic notes of the Neotropical alderfly genus Ilyobius Enderlein, 1910 (Megaloptera, Sialidae), with description of a new species, Deutsche Entomologische Zeitschrift 62 (1), pp. 55-63 : 55

Taxon classification Animalia Megaloptera Sialidae

Genus Ilyobius Enderlein

Ilyobius Enderlein, 1910: 381. Type species: Sialis flavicollis Enderlein, 1910: 380, original designation.

Diagnosis.

Forewing length ~7.0-17.0 mm in males; ~9.0-19.5 mm in females. Body generally blackish brown, but usually with pale head and prothorax. Head generally orange to reddish brown, sometimes with dark markings on frons and vertex. Antennae pilose, more than half the length of the forewing. Compound eyes strongly prominent. Labrum ~4.0-5.0 times wider than long, lateral margins rounded, front margin slightly emarginated. Prothorax>2.0 times wider than long, pronotum uniformly orange to reddish brown, or blackish brown with pale markings. Forewing ~2.5-3.5 times longer than wide, minutely hirsute, margins pilose; costal area feebly or distinctly dilated proximally, with 5-10 distinct costal crossveins; sc-r present; Rs 2-branched; MA 2-branched; MP 2-branched, anterior branch simple, posterior branch bifurcated; CuA 2-branched, CuP simple; 1A simple, 2A 2-branched, 3A simple; 3 r-rs present. Hindwing ~2.5-3.0 times as long as wide; 2-5 distinct costal crossveins present proximally; sc-r absent; Rs 2-branched; MA 2-branched; MP 2-branched; CuA 2-branched, CuP simple; 1A simple, 2A 2-branched, 3A simple; 3 r-rs present. Male tergite 9 transversely arched; sternite 9 broadly lingulate, posteriorly sometimes with elongate median projection; gonocoxites 9 widely separated from each other, generally short and ovoid, but complicatedly shaped in some species; ectoproct paired, or largely paired but medially connected by feebly sclerotized, narrow region; gonocoxites 11 transversely arched, posteriorly with a pair of median processes (= gonostyli 11), which are variously shaped among species; endophallus internally with blackish thorny setae. Female sternite 7 broad, usually with a tubercular median projection near posterior margin; fused gonocoxites 8 and gonapophyses 8 forming a strongly sclerotized complex; tergite 9 strongly broadened ventrally, separating an independent dorsal region, which is much narrower and extending ventrad; gonocoxites 9 valvate, ovoid, posteriorly bearing rather small gonostyli 9.

Distribution.

The extant described species are recorded from Argentina, Bolivia, Brazil, Chile, Colombia, Mexico, Panama, Peru, and Venezuela. In addition, an undetermined species was recorded in Ecuador ( Contreras-Ramos 2008). Considering fossils, Ilyobius might have been distributed in Eurasia based on the two species described from the Eocene Baltic ambers ( Wichard 1997, 2002) although their generic placements need further clarification ( Liu et al. 2015). Another species from the Miocene Dominican amber ( Engel and Grimaldi 2007) indicates the past occurrence of Ilyobius in Dominica.