192 THE BREEDING OF ANIMALS 



while the worker bees are sexually imperfect. It seems 

 to be true that the eggs developing into worker bees 

 and queens are identical. The one becomes a queen as 

 the result of a " royal " diet, while the worker larvae 

 are fed on a " common " diet and develop into the non- 

 fertile female. Investigations with wasps by Von Siebold l 

 and butterflies and moths by Mrs. Treat suggest a real 

 connection between nutrition and sex offspring. Schenk 

 found that starvation produced fewer males, but later 

 the same condition resulted in producing more males. 

 Busing reported that among the Swedish nobility the 

 proportion of sexes was 98 boys to 100 girls, and in the 

 Swedish clergy 108.6 boys to 100 girls. Punnett submits 

 evidence that in London more girls are born among the 

 poor than the rich. In most of 'the cases cited there are 

 too many other factors involved to justify the conclusion 

 that nutrition alone is responsible for the proportion of 

 the sexes. 



183. The maturity of the ovum. The degree of 

 development or maturity of the ovum itself at the time 

 of fertilization has a controlling influence on sex in the 

 opinion of some breeders. If fertilization occurs during 

 the early part of the heat, the offspring will be female. 

 If the ovum is fertilized later in the heat, the offspring 

 will tend to be males. Thus Thury 2 of Geneva says, 

 " The sex depends upon the degree of maturity of the 

 egg at the moment of fecundation, that which has not 

 reached a certain degree of maturity producing the female, 

 and, if fecundated when this point of maturity has passed, 

 producing a male." These results are not altogether 

 consistent with ordinary farm practice or with the experi- 



1 Rolph, W. H., "Biologische Probleme," Leipsig, 1884. 



2 Country Gentleman, 1864, p. 12. 



