166 American Midland Naturalist Monograph No. 3 



states will be noted in the individual descriptions. Larva: The head hairs vary 

 greatly in their position and branching. The siphon is usually short, with a 

 single pair of subventral tufts never inserted near base; pecten present. Anal 

 segment always with a barred area, the ventral brush rarely reduced. Comb 

 scales variable in shape and number. 



Keys to the Species 

 adult females 



1. Proboscis with a white ring near middle 2 



Proboscis without a white ring near middle 5 



2. Abdomen with a white to yellow dorsal median longitudinal stripe or dorsal 



median longitudinal row of disconnected spots; wing scales either intermixed 



dark brown and white or entirely dark 3 



Abdomen with transverse basal bands of white scales, but lacking a pale median 

 longitudinal stripe; wing scales entirely dark laeniorh^nchus (Wied.), p. 209 



3. Wing scales entirely dark; first segment of hind tarsus without a pale median 



ring; last segment of hind tarsus entirely white miichellae (Dyar), p. 195 



Wing scales intermixed dark-brown and white; first segment of hind tarsus with 

 or without a pale median ring; last segment of hind tarsus either entirely white 

 or dark on apical half 4 



4. Lateral pale markings of abdomen white, the dorsal pale markings yellowish; 



first segment of hind tarsus with a definite yellow median ring; last segment 



of hind tarsus entirely white solUcitans (Walker), p. 199 



Lateral and dorsal pale markings of abdomen both white; first segment of hind 

 tarsus variably marked (if a median pale ring is present, it is white, not yel- 

 low) ; last segment of hind tarsus white basally, dark apically, rarely all 

 white - - nigromaculis (Ludlow), p. 197 



5. Integument of scutum bright yellow, except for a pair of large dark brown to 



black postero-lateral spots; proboscis yellow scaled, dark at tip 



fulvus pollens Ross, p. 185 



Scutum and proboscis not as described above 6 



6. Tarsal segments, at least on hind legs, with white rings 7 



Tarsal segments without white rings 15 



7. Tarsal segments white-ringed only basally 8 



Tarsal segments white-ringed both apically and basally 12 



8. Scutum with a very conspicuous lyre-shaf)ed marking of white scales against a 



dark background aegppfi (Linn.), p. 227 



Scutum without such markings 9 



9. Wing scales entirely dark, narrow; basal white rings of hind tarsus usually very 



narrow, no broader than the diameter of the tarsal segments (basal rings some- 

 times rather broad, however, on segments 1 and 2) 10 



Wing scales intermixed dark and white, either narrow or very broad; basal 

 white rings of hind tarsus broad (several times broader than diameter of 



tarsal segments) 1 I 



10. Lower mesepimeral bristles absent; seventh abdominal tergite mostly dark scaled 



dorsally except for white scaling at apex vcxans (Meigen), p. 230 



A few lower mesepimeral bristles present; seventh abdominal tergite entirely 



pale scaled canlator (Coq.), p. 176 



1 L Wing scales very large, broad, deltoid; scutum with a broad median longitudinal 

 stripe, pale golden-brown on anterior half, dark bronzy-brown on posterior 

 half grossbecl(i D. and K., p. 188 



Wing scales moderate in size, narrow, llgulate; scutum with a broad median 

 longitudinal stripe, bronzy-brown for its entire length ..siimulans (Walker), p. 206 

 12. Wing scales intermixed dark brown and white, the white scales predominating; 

 abdomen entirely white scaled dorsally, except for a pair of submedian black 



patches on each segment (segments VI and VII often entirely white) 



dorsalis (Meigen) , p. 1 79 



