516 ANNUAL REPORT SMITHSONIAN INSTITUTION, lf>20. 



peculiarity. To proceed logically, let us ask first how it comes 

 about that the neuters are exclusively females in the societies of 

 hymenoptera, which are, indeed, essentially feminist societies, while 

 they are of both sexes among the termites, where a male lives with 

 a female. This peculiarity is related to another strange fact which 

 we find among the social hymenoptera — the fact that the male is 

 born from an egg which is not fertilized. 



First formulated as an hypothesis by Dzierzon, this partheno- 

 genesis has been demonstrated indirectly by the fact ascertained 

 by Duesberg for the wasps, by Meves for the domestic bee, by Lams 

 for the ants, that in the spermatogenesis of these insects there is no 

 karvogamic reduction. Of the two kinds of spermatozoa which are 

 produced, as among the other animals, one contains no chromosomes 

 and dies while the other includes all the chromosomes of the 

 spermatogonia. The corrolary of this is that the nuclei of the male 

 should be haploidic — that is, containing only half the number of 

 chromosomes of the nuclei of the female, the latter being diploidic, 

 as in the other animals. The positive demonstration of this difference 

 is, however, yet to be made. The absence of karyogamic reduction 

 confirms the fact, ascertained among the wasps and bees by von 

 Siebold, that the egg giving birth to a male contains no spermatozoa. 



Is this phenomenon peculiar to the societies of hymenoptera? Is 

 it a social peculiarity which could have as a useful consequence 

 an economy of spermatozoa allowing the fertilized female to pro- 

 duce more neuters? It is not probable, for it would presuppose a 

 peculiar polygenism. It is more likely that it already exists among 

 the ancestral solitary forms, and a special study of the spermato- 

 genesis of the diggers should be able to prove it. 



It is acknowledged that the seminal receptacle of the fertilized 

 female of the social hymenoptera can be contracted to let out the 

 spermatozoa which it contains. If the organ contracts after the 

 egg laying, a spermatozoa penetrates into the egg and that one pro- 

 duces a female individual; if the receptacle does not contract, the 

 egg remains untouched and produces a male. 



M. Paul Marchal has tried to complete this explanation in an 

 ingenious manner. Being granted that the different kinds of eggs 

 succeed each other in a regular manner during the egg laying of 

 the social hymenoptera, that the female first for a long time lays 

 eggs from which come neuters — therefore fertilized eggs, since the 

 neuters are female — then eggs of males, and finally eggs of perfect 

 females, he supposes that a time arrives when the seminal receptacle 

 of the female is fatigued and ceases to function, to take up its 

 activity later. 



It is this regular succession in the laying of fertilized and non- 

 fertilized eggs, manifesting itself either during the one-year life 



