214 U.S. NATIONAL MUSEUM BULLETIN 277 



Length: Male body 3.5 mm., wing 2.1 mm.; female body 5.2 mm., 

 wing 2.5 mm. 



Type-locality: Suchiapa, Chiapas, Mexico; 25 March 1953 (R. C. 

 Bechtel and E. L. SchUnger). 



Holotype: Male (CAS) 8937. 



Allotype: Female, El Rancho, Guatemala; 17 February 1932 

 (C. N. Ainslee) (USNM). 



Genus Metatrichia Coquillett 



Metatrichia Coquillett, 1900, p. 500. 



Type-species, Scenopinus bulbosus Osten Sacken (original designa- 

 tion). The genus Metatrichia Coquillett is characterized by large ro- 

 bust flies with broad, flat, blunt abdomens. Cell R5 in the wing is 

 closed, vein R4 branches from various points along the cell. The heads 

 are higher than long and the front bulges at the middle projecting the 

 antennae forward. The genus is represented in all regions but the 

 Palaearctic. 



Key to the Species of Metatrichia 



Wing hyaline 2 



Wing brown or yellow brown 4 



2. Halter knob brown 3 



Halter knob white, antenna yellow, pointed, thorax with white hairs, abdomen 



with white bars with anteriorly directed swelling55 laterally. (Africa) 



cf M. stevensoni (Bezzi) 



3. Body with flattened scale-like hairs (North America) 



cf M. bulbosa (Osten Sacken) 

 Body only sparsely covered with microscopic scales (Austraha) 



cfM. waterhousei (Paramonov) 



4. Wing brownish 5 



Wing yellow-brown, halter knob cream, antenna dark red-brown, body with- 

 out scale-like hairs (S. America) cfM. robusta (Krober) 



5. Halter knob brown or yellow-brown 6 



Halter knob orange-brown or tannish yellow 7 



6. Halter knob brown, body covered with white flattened scale-like hairs (North 



America) 9 M, bulbosa (Osten Sacken) 



Halter knob yellow-brown, antenna black-brown, velvety, body without 

 flattened scales (S. America) 9 M. robusta (Krober) 



7. Halter knob orange-brown, a very large fly over 7.5 mm. (Africa) 



9 M. lophrysoma (Speiser) 



Halter knob tannish-yellow a moderate sized fly under 5.5 mm., antenna 



orange at base dark at tip (Africa) 9 M. stevensoni (Bezzi^ 



