HYMENOPTERA 



975 



In the most generalized bees, the Prosopidas, the proboscis is com- 

 paratively short and the labium is either notched at the tip {Prosopis, 

 Fig. 12 1 7) or is quite deeply bifid {Colletes, Fig. 12 18). In all other 

 bees the labium is pointed at the tip. Among the bees with a pointed 

 labium the proboscis varies greatly in length; in some (Sphecodes, 

 Fig. 1 2 19) it is comparatively short, while in the more specialized 

 forms, as in Apis (Fig. 1220) it is greatly elongate. 



Fig. 12 1 7. — Pro- 

 boscis of Pro- 

 copis. (After 

 Saunders.) 



Fig. 12 19. — Probos- 

 cis of Sphecodes. 

 (After Saunders.) 



Fig. 12 1 8. — Probos- 

 cis of Colletes. 

 (After Saunders.) 



Fig. 1220. — La- 

 bium of the 

 honey-bee. (Af- 

 ter Saunders.) 



The two sexes of bees differ in the number of abdominal tergites 

 exposed to view; in the male there are seven, in the female, only six. 



The different species of bees exhibit great differences in habits; 

 some are solitary; each female providing a nest for her young; 

 some are parasitic, the females laying their eggs in the nests of other 

 bees and the larvee feeding on the provisions stored by their hosts; 

 and some are social, living in colonies consisting of many individuals. 



The social bees are the honey-bees, the bumblebees, and the 

 stingless honey-bees of the Tropics. In all of these, as with the social 



