No. 22.] HYMENOPTERA OF CONNECTICUT. 759 



ment and base of second, and on mesonotum, mostly or en- 

 tirely yellow separatus 



Ocelli located below narrowest part of front; malar space 

 approximately one-half as long as wide; third antenna! 

 joint equal in length to fourth and fifth joints combined; 

 mesonotum, first, second, and third dorsal abdominal seg- 

 ments and sometimes fourth also, with part or all of their 

 pubescence, yellow auricomus 



B. separatus Cresson. 



New Haven, May, 1903 (W. E. B.). 



B. auricomus Robertson. 



Branford, 22 May, 1905 (H. W. W.). 



Psithyrus LePeletier. 

 In this genus we have the false or parasitic bumble-bees. 

 They have no workers, only queens and males, and live at the 

 expense of their hosts, the true bumble-bees. 



Key to Species, 



Females. 



1. Abdomen finely punctate 2 



Abdomen coarsely punctate; pubescence long, coarse, blunt; 

 third dorsal segment usually, first, second, and fourth 

 often, more or less yellow laterally; pleurae yellow; meso- 

 notum yellow, often with some black hairs on its disc laboriosus 



2. Abdominal pubescence short, fine, black, rarely a little yellow 



on lateral apical margins of fourth dorsal segment; pleurae 

 and space between wings with black pubescence ...variabilis 

 Abdominal pubescence long, i mm. or nearly i mm. in length, 

 black except on third and fourth dorsal segments, on the 

 former of which part of the pubescence is pale yellowish, 

 and, on the latter, it is all yellowish; pleurae and posterior 

 half of dorsum of thorax with black pubescence; wings 

 brownish ashtoni 



Males. 



1. Pleurae entirely covered with yellow pubescence; fourth dor- 



sal abdominal segment covered with entirely black pubes- 

 cence 2 



Pleurae at least partly covered with dark brown or black pu- 

 bescence 3 



2. Dorsulum with black hairs in center laboriosus 



Dorsulum with a transverse band of black pubescence 



laboriosus van contiguus 



