348 ERNEST A. BACK. 



9 ■ — Reddish-brown; antennae, palpi and legs of same color; head 

 and entire thorax light golden pruinose, on the thoracix dorsum nearly- 

 concealing the three usual stripes. Abdomen reddish; posterior lateral 

 margins of segments 1-5 white pruinose; the extreme base of the first 

 segment, the broad anterior portion of the following four, the remaining 

 segments on the sides narrowly, and the venter black ; on segments 

 2-4 the black band is much narrowed in the middle, on segment 5 

 usually interrupted. Halteres reddish. Legs usually without any 

 traces of black on the femora. Wings yellowish hyaline, apex broadly 

 blackish. Clothing of entire body pale yellow and reddish, the short 

 fine hair of the abdomen often being black on the black areas. 



Type. — -Types of both adustus and combustus are at the M. 

 C. Z. 



//a6j7a^. ^Clarendon (C. R. Jones, Aug. 11), Tex.; Wallace, 

 Grove, and Hamilton Counties (F. H. Snow, July, 3,000 ft.), 

 Ks.; Ft. Collins (July 11), Col. 



I have seen the types of both adustus and combustus and, 

 with the small amount of material at Loew's disposal, they 

 appear distinct enough. Nevertheless the examination of a 

 considerable number of specimens of both species has led me 

 to consider adustus the female of combustus. My reasons are 

 that combustus is always represented by males and adustus 

 by females; that they are collected at the same time and 

 place; that adustus shows the same line of variation from 

 combustus as does the female of dispar, a nearly related species, 

 from its male, and as does bicolor from abbreviatus which I 

 have recently seen in coitu. So while I have never seen com- 

 bustus and adustus in coitu, or been able to form a complete 

 gradation from one to the other as can be done with males 

 and females of dispar, I feel confident that future collecting 

 will bear me out in uniting the two. 



Saropogon coquillettii n. sp. 



(^ 9- — -Length 14-16 mm. — Thorax grayish-white pruinose, yellower 

 on the dorsum; scutellum with four bristles: abdomen slender, red- 

 dish, with white pruinose and black spots on the sides; the black spots 

 sometimes forming cross-bands over the terguin; hypopygium and 

 venter black; wings hyaline, not black or brown. 



r^. — -Ground color of head and thorax black. Head wholly white 

 pruinose; the dense row of bristles forming the mystax; the occipital 

 and frontal bristles and beard white ; antennas, palpi and proboscis 



