THE WEB OF LIFE 341 



inviolate. The number of drones is also reduced, as 

 we have just noted, by the nuptial flight. But there 

 remains for the survivors — ^whether adults or larvae — a, 

 tragic death at the hands of the workers and nurses. As 

 the result of this Lycurgan tragedy there are no drones left 

 at the end of the season. It seems rather noteworthy that 

 while the venom of a cobra is not deadly to another cobra, 

 the formic acid of the bee's sting seems to be fatal to 

 another bee. 



Evolution of Social Bees 



Let us inquire into the evolution of social bees, utihzing 

 especially the studies of Dittrich and Buttel-Reepen. 

 The social mode of life is marked, as every one knows, by 

 three distinctive features : (1) -the differentiation of 

 fertile females (queens) and normally non-fertile females 

 (workers) ; (2) the utUization of wax for some kind of 

 comb ; and (3) the accumulation of stores, especially of 

 pollen and nectar. Between the highly evolved social 

 Ufe of the hive-bees and the life of the sohtary bees there 

 are many transitional stages, and although we cannot 

 display the pedigree of the hive-bee, nor arrange the stages 

 in what was the actual historical sequence, we can see how 

 very gradual the transition from sohtary to social may have 

 been. The following, is Dittrich's series : — 



I. — ^Bees living alone : — 



(a) The mother dies after egg-laying and providing food 

 for the larvae, but without ever seeing the brood. 



1. The nests are formed quite apart : Prosopis, Ceratina, 



Osmia papaveris, etc. 



2. The females work independently, but the nests are 



formed in colonies, and there may be mutual aid 



