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 1 and also by Leuckart. 2 
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. Area. 
Naturgesch., XL. 
