Mik, J. 1866. Beitrag zur Dipterenfauna des Osterreichischen Kustenlandes. Verhandlungen der Zoologisch-Botanischen Gesellschaft in Wien 16: 302.


Thaumastoptera (Thaumastoptera) is a group of small flies (2-5 mm) comprised of 7 presently known species. Although small in numbers, the genus has a wide distribution and is found in all biogeographic regions except the Neotropical and Australian/Oceanic Regions. Thaumastoptera (Thaumastoptera) is defined by the combination of the following characters: presence of CuA crossvein near the wing midlength, the absence of the discal cell (dm), and the characteristic gonostylus of the male genetalia.


Head: Anterior vertex suppressed. Rostrum length less than that of the remaining head. Maxillary palpus length less than or subequal to that of remaining head; palpomeres subequal. Antennae: 16 articles; antenomeres variable (oval, cylindrical, or moniliform).

Thaumastoptera (Thaumastoptera) hynesi  wing
Figure 1. Wing of Thaumastoptera (Thaumastoptera) hynesi Alexander (redrawn from Alexander 1967; scale bar = 1.0 mm).

Wings: Subhylane, commonly patterned with clouds of brown located along veins; cells without microtrichia; anal angle of wing present. Wing venation: Sc2 removed from Sc1, Sc2 ending before origin of Rs, Sc1 ending between origin of Rs and split of Rs; R1+2 in near alignment with R2, R2 subequal to longer than R1+2; two branches of Rs (R4, R5) attaining wing margin; two medial veins (M1+2, M3) attaining wing margin; cell dm absent; anterior wing chord not in alignment by presence of CuA intersecting M near midlength of wing; two Cubital veins (CuA1, CuA2) attaining wing margin; two Anal veins (A1, A2) attaining wing margin.

Thaumastoptera (Thaumastoptera) sp. hypopygium
Figure 2. Male hypopygium of Thaumastoptera (Thaumastoptera) sp. (scale bar = 0.5 mm).

Male hypopygium: 9th tergite (9t) and sternite (9s) laterally divided. Mesoventral lobe of gonocoxite absent. Gonostylus singular, the style a spatulate rod narrowing to an curved blunt apex, base of style with a prominent tooth. Aedeagus simple with one or two terminal openings. Proctriger simple, without modification.


Thaumastoptera (Thaumastoptera) is a small genus with a widespread distribution. The genus is distributed in the Nearctic (1 species), Western Palearctic (3 species), Eastern Palearctic (1 species), Afrotropical (2 species), and Oriental (2 species) Regions. In the Oriental Region one species is known from the Philippines and one from the Tamil Nadu region of India.

Larval Habitat: 

The larvae of Thaumastoptera (Thaumastoptera) are aquatic and found in the fine sediment of small streams, springs and seeps (Byers 1996)