No. 22.] HYMENOPTERA OF CONNECTICUT. 741 



C. americanus Cresson. 

 C. aestivalis Patton. 



C. sp. 



Torrington, 7 July, 1905 (W. E. B.). 



STELIDIDiE. 



Black bees, with whitish margins to the dorsal abdominal 

 segments. Represented by a single genus. 



Stelis Panzer. 

 Key to Species. 



Females. 



Abdomen with narrow, continuous or interrupted whitish 



fasciae on its dorsal segments fcederalis 



Abdomen with eight to fourteen whitish spots above . . . .lateralis 



Males. 



Third ventral abdominal segment with a median apical denti- 

 form carina; first to fifth dorsal segments with narrow, 

 continuous or interrupted whitish fasciae fcederalis 



Third ventral abdominal segment simple; first to fifth dorsal 

 segments with lateral whitish spots lateralis 



S. (Microstelis) foederalis Smith. S. nitida Cresson. 

 S. (M.) lateralis Cresson. 



MEGACHILIDJE. 



To this family belong the leaf-cutter bees and the bees para- 

 sitic upon them, as well as the mason-bees. 



Key to Genera. 



Females. 



1. Abdomen not maculated 2 



Abdomen maculated, claws cleft; abdomen with a scopa; 



apical tarsal joint with an empodium; mixillary palpi with 

 two joints Dianthidium p. 752 



2. Empodii absent; maxillary palpi 3-jointed; first dorsal abdom- 



inal segment with a broad concavity 3 



Empodii present; claws simple; abdomen with a scopa 4 



3. Abdomen with a scopa; axillae not produced into spines on 



each side of scutel Megachile p. 742 



Abdomen without a scopa; axillae produced into spines on 

 each side of scutel Ccelioxys p. 746 



