OTHER METHODS OF SEX-DETERMINATION 235 



The evidence, taken at its face value, appears to mean 

 that the haploid number of chromosomes produces a 

 male, the diploid a female. The presence of sex-chromo- 

 somes is nowhere apparent, hence the presence of specific 

 sex genes cannot be assumed. Even if the absence of such 

 genes be granted, it is not apparent why the half number 

 of chromosomes should produce a male and the diploid 

 number a female, unless the differential factor here in- 

 volved be the relation between the amount of cytoplasm 

 in the two kinds of eggs and the number of chromosomes 

 present. Even then, however, the result is difficult to 

 bring into accord with the case of the bee (described 

 below), where the diploid egg, that produces a female, 

 and the haploid egg, that produces a male, have the same 

 size. The outstanding fact in both cases is that the hap- 

 loid number of chromosomes determines the male sex, 

 even although something else determines which eggs be- 

 come haploid. 



It might be possible to invent an explanation involving 

 sex-chromosomes if two kinds of X-chromosomes were 

 postulated and if, at the reduction division, one passes 

 out into the polar body of the male egg and the other one 

 from the sexual egg (both being retained in the partheno- 

 genetic egg) ; but it must be confessed that at present 

 there is no excuse or need perhaps for advancing such a 

 speculation. 



Sex-determination in bees, and in their near relatives, 

 the wasps and ants, is also connected with the diploid and 

 haploid condition of the nuclei. The facts seem well estab- 

 lished, but the interpretation here is also obscure. The 

 queen bee deposits eggs in the queen-cells, in the worker- 

 cells, and in the drone-cells. These eggs are, before being 

 laid, all alike. The eggs in the worker-cells and the queen- 

 cells are fertilized at the time of deposition ; in the drone 

 cells the eggs are not fertilized. All eggs give off two 



