AKT. 11 CHRYSOTOXINE SYEPHID-FLIES SHANNON S 



countries, but these probably occur only in high altitudes. One 

 species recorded here from India {lad^akense, new species) was taken 

 at an altitude of 16,000 feet. Very little is known of their immature 

 stages. A pupa of puhescens has been found under a stone. 



KEY TO THE SPECIES OF CHRYSOTOXUM IN THE NATIONAI, COLLECTION 



AS Arista as long as, or longer than, combined length of first and second an- 



tennal joints (fig. la and 16) Subgenus Primochrysotoxum. 



B\ American species. 



C\ Apical corners of tergites not projecting (fig. 2) ; outline of abdo- 

 men evenly rounded (best viewed from below) ; third sternite 

 with yellow markings extending upon anterior margin in colora- 

 dense and sometimes in derivatum; antenna shorter than fore 

 tarsus ; fifth tergite much broader than long. 

 D\ Second sternite black except sometimes on anterior margin ; 

 pteropleura usually with black pile ; frons of male black 

 pilose ; anterior bands on tergites 2 and 3 interrupted in mid- 

 dle and separated from side margins ventricosum Loew. 



DS Second sternite with hind margin yellow ; pteropleura and 

 frons of male yellow pilose. 

 E\ Anterior bands on tergites 2 and 3 interrupted in middle 



and separated from side margins Chinook, new species. 



ES Anterior bands on tergites 2 and 3 entire and attaining 



side margins coloradense Greene. 



C. Apical corners of tergites 2, 3, and 4, and usually the fifth in the 



female, distinctly projecting (fig. 3) ; antenna as long as, or 



longer than, fore tarsus ; fifth tergite about as long as broad. 



D\ Abdominal margins beyond middle of second tergite yellow. 



E\ Sternites 3 and 4, and in female the fifth, with yellow only 



on hind margins ; anterior bands on tergites 3 and 4 



entire aztec, new species. 



ES Sternites 3 and 4, and in female the fifth, each with a 

 pair of large yellow spots at the middle ; anterior bands 

 on tergites 3 and 4 interrupted. 

 F\ First tergite and anterior corners of second black 

 pilose ; apices of fore coxae with black hairs. 



occidentale Curran. 



FS First and second tergites yellow pilose, sometimes with 



a few black hairs ; apices of fore coxae with yellow 



hairs ypsilon Williston. 



D'. Lateral margins of tergites 2 to 5 alternating black and 

 yellow. 

 E\ Pteropleura with black pile ; no yellow spot above fore 

 coxa ; arcuate abdominal bands interrupted. 

 F\ Second antennal joint shorter that the first ; length of 



joints, 1 : 0.75 : 2.5 laterale Loew. 



F". Second antennal joint longer than the first ; length of 



joints, 1 : 1.25: 2.5 fasciolatum (DeGeer). 



ES Pteropleura yellow pilose ; a more or less distinct yellow 

 spot usually present above fore coxa. «■ 



