756 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [BuU. 



ridge forming a subquadrate sinus nearly reaching apical 

 margin; malar space shorter than wide impatiens 



8. First, second, and third dorsal abdominal segments with 



yellow pubescence; fourth segment in addition sometimes 



with all or most of its pubescence yellow g 



First and second dorsal abdominal segments, only, with more 

 or less yellow pubescence; mesonotum with some black 

 hairs; base of labrum with two tubercles or elevations.. lo 



9. Labrum bituberculate perplexus 



Latrum not bituberculate but medially impressed borealis 



10. Second dorsal abdominal segment with yellow hairs on basal 



middle bimaculatus 



Second dorsal abdominal segment with yellow pubescence 

 throughout except sometimes apically, where it may be 

 more or less black .vagans van consimilis 



Males, 



1. Hind tibiae rather evenly covered with short hair; antennae 



with fifth joint nearly as long as third and fourth com- 

 bined; vertex with black pubescence, a band of black hairs 



on mesonotum between insertion of wings 2 



Hind tibiae with short, sparse hair on outer face, posterior 

 border with its hair as long as diameter of joint S 



2. First to fifth dorsal abdominal segments not all with yellow 



pubescence 3 



First to fifth dorsal abdominal segments with yellow 

 pubescence 4 



3. First to fourth dorsal abdominal segments with yellow pubes- 



cence, fifth, sixth, and seventh with their pubescence black 

 or fulvous, or yellow with fulvous at tip, yellow with 



black at tip, or black with fulvous at tip pennsylvanicus 



First dorsal abdominal segment apparently alone with yel- 

 low pubescence (sometimes there is some yellow pubes- 

 cence at the base of second segment) impatiens 



4. Sixth and seventh dorsal abdominal segments with black 



pubescence in middle, apex with black pubescence. . .borealis 

 Sixth and seventh dorsal abdominal segments with all 

 pubescence black fervidus 



5. Vertex with part or all of its hair black 6 



Vertex with yellow pubescence; first, second, and third dorsal 



abdominal segments with yellow pubescence, fourth with 

 yellow or black pubescence, next two segments with most 

 or all of their hair black, apex of dorsum of abdomen with 

 pale hairs; venter with pale pubescence perplexus 



6. Vertex with its hair partly black ^ 7 



Vertex with all of its hair black; mesonotum with yellow 



pubescence and a transverse band of black pubescence; 



