42 Everett E. Wehr 



Humble-bee like in appearance; thorax and abdomen with thick, 

 long pile (on the dorsum of thorax sometimes blackish pilose 

 (var. melanostomiis) ; arista plumose; hind tarsi red flavipes 



7. Third abdominal segment with a posterior, velvety black cross- 

 band not interrupted in the middle '. 8 



Third segment with three opaque spots; an elongated one on 

 each side behind, and an oval median one in front; the opaque 

 of second segment with a triangular shining spot behind; fourth 

 segment with an oval opaque spot in front dimidiatus 



8. Third segment of the abdomen broadly and conspicuously yellow 

 on the sides (not so in $ ), joining the yellow of the second seg- 

 ment, the black of the second segment wholly opaque, not ex- 

 tending outwards on the sides behind; third segment with an 

 opaque spot in front; fourth segment metallic, usually with a 

 small opaque spot in front meigenii 



The third segment not conspicuously yellow on the sides; the 

 posterior opaque fascia of the second segment behind reaching 

 toward the lateral margin (meigenii ?) 9 



9. Male with anterior velvety-black cross-band not interrupted in 

 the middle on the third and fourth segments; female with no 

 velvety black cross-bands on third and fourth segments nitidus 



Male with only an anterior opaque spot on the third and fourth 

 segments (not sure of inornaUis $ ) ; female with or without an- 

 terior opaque spot on the third and fourth segments 10 



10. Lighter markings of abdomen usually quite distinct; third and 

 fourth segments with a small elongate, opaque black spot in 

 front temporalis 



Lighter markings obsolete, third and fourth segments without 

 opaque anterior spot inornatus 



11. Second, third and fourth segments of abdomen broadly reddish 

 on sides, leaving a narrow black stripe, which is wholly opaque 

 on the segment, and in front, at least, on the third segment; 

 eyes narrowly separated ( $ ) tnontanus 



Second segment of abdomen only yellow on sides, with a pos- 

 terior, interrupted or subinterrupted velvety cross-band; pos- 

 terior margin of segments 2-4 yellowish white with a fringe of 

 pale golden yellow hairs latifrons 



148 



