156 PERFECT SOCIETIES OF INSECTS. 



has been retarded, after the same number of hours she 

 begins laying male eggs, and continues to produce these 

 alone during her whole life. From hence it should seem 

 to follow, that the former kind of eggs are first in the 

 oviducts, and, if impregnation be not effected within a 

 given time, that all the worker embryos perish. Yet 

 how this can take place with respect to those that in a 

 fertile queen should succeed the laying of male eggs, or 

 be produced in the second year of her life, seems diffi- 

 cult to conceive ; or how the male embryos escape this 

 fate, which destroys all the female, both those that are 

 to precede them and those that are to follow them. Is 

 it impossible that the sex of the embryo may be deter- 

 mined by the period at which the aura seminalis vivifies 

 it, and by the state of the ovary at that time ? In one 

 state of the ovary this principle may cause the embryos 

 to become workers, in another males. And something 

 of this kind perhaps may be the cause of hermaphrodites 

 in other animals. But this I give merely as conjecture 3 : 

 the truth seems enveloped in mystery that we cannot yet 

 penetrate. Huber is of opinion that a single impreg- 

 nation fertilizes all the eggs that a queen will produce 

 during her whole life, which is sometimes more than two 

 years b . But of this enough. 



I said that forty-six hours after impregnation the 

 queen begins laying worker eggs ; this is not, however, 



a This conjecture receives strong confirmation from the following 

 observations of Sir E. Home, which t met with since it came into my 

 mind. From the nipples present in man, which sometimes even af- 

 ford milk, and from the general analogy between the male and fe- 

 male organs of generation, he supposes the germ is originally fitted 

 to become either sex j and that which it shall be is determined at the 

 time of impregnation by some unknown cause. Philos. Trans. 1 799. 

 157. b i. 106 



