The Reproductive Processes and Parthenogenesis 191 



the male chromosomes. While this theory would readily 

 explain the great variation in such hermaphroditic bees it 

 is based on the assumption that sex is determined by fertili- 

 zation, .which may be questioned. 



Eggs which fail to hatch. 



In some cases, one of which came under the author's 

 observation, queens are normally mated and lay eggs, but all 

 the eggs fail to hatch. This is perhaps due to some abnor- 

 mality of the queen, and in the case examined it appeared 

 that the failure to hatch might have been due to the evap- 

 oration of the water in the protoplasm through the unusually 

 thin and soft chorion of the eggs. Similar cases were de- 

 scribed by Claus and v. Siebold ' and also by Leuckart.^ 



1 Claus u. V. Siebold, 1873. Ueber taube Bienen-eier. Zeit. f . wiss. Zool., 

 XXIII, pp. 198-210. 



2 Leuckart, R., 1875. Ueber taube u. abortive Bieneneier. Arch. 

 Naturgesch., XL. 



