AMERICAN DIPTERA. 185 



2. Venter of abdomen wholly black 3. 



Venter of abdomen largely yellow ventral is. 



3. Abdomen with white pruinose spots 4. 



Abdomen without pruinose spots abdominalis. 



4. Females*: thorax and legs chocolate colored, last two segments of 



abdomen black eutrophus. 



Males: thorax black, usually yellowish above.... rhsidaiiiantliiis. 



Ospriocerus abdominalis (PI. VII, fig. 5). 



Asilus abdominalis Say, Long's Exped., App., 375; 1824, Comp. 

 Works, I, 255. 



Dasypogon ceacus Wiedemann, Auss. Zw., I, 390, 1828. 



Dasypogon spathulatus Bellardi, Saggio, II, 82, pi. I, fig. 9, 

 1861. 



Ospriocerus csacides Loew, Cent., VII, 51, 1866. 



Ospriocerus ceacus Osten Sacken, West. Dipt., 290, 1877. 



Ospriocerus abdominalis Coquillett, Ent. News, IX, 37, 1898. 



Ospriocerus abdominalis Jones, Trans. Am. Ent. Soc. XXXIII, 

 275, 1907 (locality note). 



Ospriocerus abdominalis Howard, Insect Book, 1902, PI. XIX, 

 fig. 5. 

 % $. — Length 13.5-19 mm. — Black, subpolished; abdomen orange- 

 red above, without white pruinose lateral spots; wings blackish. 



Face and occiput silvery white pruinose; mystax sparse, composed 

 of long rigid bristles covering the swollen lower half of the face; vi- 

 brissa? confined to the middle of the upper portion of the same, com- 

 posed of the short, downward directed bristly hair. Antenna? black, 

 the depression in the inner distal half of segment three very distinct. 

 Bristles of the vertex of good size, forward directed; occiput, pro- 

 thorax and coxae very bristly. Dorsum subpolished, often covered 

 with a thin hoary bloom. Segment 1 of the abdomen, base of segment 

 2, lateral margins of the following segments, genetalia and venter, 

 black; posterior margin of the second and the following segments 

 above, yellowish-red or red. The female differs from the male in that 

 the last two segments of the abdomen are polished black. Legs 

 wholly black, with many but short bristles; claws black, red at base. 

 Wings blackish, subopaque, with steel-blue reflections; fourth posterior 

 cell closed and petiolate. Clothing of the entire body deep black, the 

 fine hair upon the red portion of the abdomen alone being yellowish- 

 red. 



Type. — Lost. 



* This does not include the eutrophus female from Kansas, or the 

 two males with the reddish thoracic dorsum at the National Museum 

 mentioned below. 



TRANS. AM. ENT. SOC, XXXV. (24) MAY, 1909. 



