Matileola thaii (after Papp, 2005)
Matileola thaii is an easily recognisable species. As for its wing venation, it seems to be the most primitive species of the known lygistorrhinids. That is, wing venation is less reduced than in any other species. Contrarily to the other two species, also its fore coxae are dark. Its male genitalia are of the same structure as of the other two species, but there are distinct and well-discernible differences. Its gonostylus is definitely shorter and the sub-basal megaseta on gonostylus is stronger than in the other two species. There are much less microchaetae on tergite 8, than on that of the other two species.
Male. All body, including abdominal tergites dark, no lighter area on thorax.
Head. Male frons linear, facettes comparatively large, round, microtrichia between them distinct. Two large lateral ocelli. Antenna all dark, 0.37 mm long.
Thorax rather dull. Mesonotal microtrichia short: a sagittal acrostichal and 2 dorsocentral rows are distinct. Only supra-alar and postalar setae of thorax are stronger.
Legs all dark, incl. fore coxa. No stronger setae on legs but femoral and tibial microtrichia are comparatively long as in congeners. Microtrichia are ordered in more or less regular rows. Fore tibia 0.53 mm long, fore metatarsus 0.515 mm. Fore and mid tarsi are thin. No tibial spur on fore tibia, but I do not see a spur either on mid tibia. Hind tibia baseball-bat shaped, length 1.12 mm, hind metatarsus 0.61 mm long, breath 0.11 mm. Hind tibia with a 0.19 mm long medial and a 0.09 mm long lateral spur.
Wing uniformly brown, not spotted. Costal and radial veins light brown, other veins lighter brown. Vein R1 reaches 0.99 mm from wing base, i.e. ends at 0.42 of wing length. Costal vein thick from its conjointment with R1 to its apex. Costa ends at 13/19 of distance of R5 and M1. R5 widely S-shaped. M-Cu fork complete, Cu1 joins base of R close to wing base. M2 complete, i.e. well pigmented to the base of fork, M1 nearly so; stalk of M fork is as faint as in the other two species. Cu1 curved arched; Cu2 straight, parallel to Cu1, and continued slightly distally to base of M-Cu, fork. A1 faint and close to and parallel with hind wing margin. Halter black, base of stalk lighter, length 0.53 mm (holotype).
Abdomen very thin and about as long as wing, tergites all dark. Tergite 9 broad and slightly longer than gonocoxites; its basal part seems slightly shorter than that of the other two species. Tergite 8 with rather few microchaetae. Gonocoxites without any conspicuous armature. Gonostylus much shorter than gonocoxite, and conspicuously shorter that that of M. similis and M. yangi. Contrarily, its medial sub-basal megaseta stronger, and macrosetae less dense apically.
Female unknown.
Measurements in mm: length of head 0.27, length of thorax 0.41, length of head and thorax together 0.61, length of abdomen 2.25, total body length ca. 2.85 (holotype), body length of paratype ca. 2.9, wing length 2.42 (holotype), 2.37 (paratype), wing breadth 0.75, 0.76, length of proboscis 0.65 (holotype), length of palpus maxillaris 0.285.