18 



Riley Presidential Address. 



The architecture of certain solitary bees is shown in Figs. 4 

 and 5. These solitary bees, no matter in what situations or of 

 what material they make their cells, generally store them with 

 honey or pollen, and after depositing an egg, cap the cell and 

 leave the young larva to care for itself. The habits of the social 

 Bumble-bee (Bombus) are but a step in advance, as the larvae are 



FIG 5. ARCHITECTURE OF BEES (continued) : 4, larva of Xvlocopa ; 8, leaf-ciittci bee, 

 Megachile\ 9, cells of Megachilc in elder ; 10, larva of ^upholsterer bee, Ceratina (lupin 

 enlarged; u, cells of same in elder, ; 13, cells of Osmia s.milima in deserted oak-^all ; 

 14, earthern cell of same ; 15, pollen massof Osmia natural size (After 1 ackard.) " 



developed in a mass of pollen and honey, in which they form 

 rather imperfect cells. When full grown each spins a silk cocoon 

 which is thickened by a certain amount of wax, which is added by 

 the adult bees. The females labor and several co-operate in the 

 same nest. In the Bottle-bees (Melipona) a still further step is 

 seen, as the cells, of a rather dark, unctuous wax, are formed into 

 regular combs and are somewhat imperfectly hexagonal. They 

 are, however,, in single horizontal tiers, separated and supported 

 by intervening pillars, more like the nests of the social wasps, and 

 the cell is sealed after the egg is laid upon the stored food, just as 

 in the case of solitary bees. The honey is stored in separate flask- 

 like cells, and but one queen is allowed to provide eggs. 



