306 U.S. NATIONAL MUSEUM BULLETIN 277 



Key to Species of Riekiella 



1 . Vein M 1 + 2 not reaching vein R5 or edge of wing 2 



Vein M 1 + 2 ending in R5 before tip of wing. 6 



2. Males 3 



Females 4 



3. Wing smoky with a scaly appearance, R4 branching beyond the middle of 



vein R5 R. complexa, new species 



Wing brownish, halter knob tan with a brown rib, vein R4 branching before 

 the middle of vein R5, dorsal lobes of ninth segment ending in wiry 

 hooks R. uncata, new species 



4. Wing brownish 5 



Wing hyaline, vein R5 bending backward beyond the branching of vein R4, 



halter yellow, very large R. bicornis Paramonov 



5. Halter knob yellow-brown, darker at base, antenna black-brown, R4 branch- 



ing from R5 near the center of the vein, running straight to the leading 



edge of the wing R. uncata, new species 



Halter knob orange-brown with a tan median band, R4 branching from near 

 the basal third of R5 and curving "S"-like to the leading edge of 

 wing R. collessi, new species 



6. Males 7 



Females 9 



7. Wing brownish 8 



Wing hyaline, halter knob brown with a tan ventral stripe, ninth tergum 



one-fourth length of body, with upper and lower sections equal in 

 length R. quadrifida, new species 



8. Halter knob dull yellow with a dorsal brown rib to the tip, ninth tergum 



one-fourth the length of the body, the dorsal portion pointed and nearly 

 twice as long as the rounded ventral portion . . . R. taylorl, new species 

 Halter knob tan-brown, ninth tergum short, dorsal portion pointed, ventral 

 portion hooked, aedeagal parameres extending beyond ventral portion of 

 ninth tergum R. collessi, new species 



9. Wing hyaline 10 



Wing smoky brown, granular, halter knob creamy white, vein R4 branching 



from near center of cell R5, ending in leading edge of wing beyond the tip 



of cell R5 R. dycei, new species 



10. Halter knob brown with a tan stripe below, antenna black, tip of cell R5 



pointed, small under 4 mm R quadrifida, new species 



Halter knob light brown above, cream below, antenna with third segment 

 orange at base, tip red-brown, cell R5 blunt at tip, eighth sternum pointed 

 much longer than tergum; a large fly over 6 mm. 



R. longiventris, new species 



203. Riekiella bicornis Paramonov 



Figure 197 



Riekiella bicornis Paramonov, 1955, p. 653. 



The type of this species is figured for the first time. Of interest are 

 the venation of the wing and the structure of the eighth sternum which 

 far exceeds the dorsum and the extent of the ninth segment. 



Length: Female body 3 mm., wing 2 mm. 



