Volume I AUGUST. 1911 No. 3 



SOME STAGES IN THE SPERMATOGENESIS 

 OF ABRAXAS GROSSULARIATA AND ITS 

 VARIETY LACTICOLOR. 



By L. DONCASTER, M.A., 

 Fellow of King's College., Cambridge. 



It has been shown by various cytologists, especially in the United 

 States, that in certain insects and other animals, the sex of the 

 individual is related to the presence or absence of a particular 

 chromosome in the nucleus of one of the gametes from which that 

 individual was produced. It has also been frequently pointed out 

 that the behaviour of the chromosomes in the maturation of the 

 gametes is exactly adapted to bring about Mendelian segregation, if 

 the members of an allelomorphic pair of characters are determined 

 by a pair of chromosomes which separate in gametogenesis. In the 

 Currant Moth {Abraxas grossulariata) I have shown ^ that a pair of 

 very definite Mendelian characters is intimately associated with sex, 

 in such a way that one of them is never borne (before fertilisation) 

 by eggs which will produce females. The two forms have the typical 

 grossulariata character, and the lacticolor character respectively, and 

 breeding experiments show that the grossulariata determinant is never 

 borne by female-determining eggs. It therefore seemed that a study 

 of the gametogenesis of this species oflfered exceptional hope of showing 

 the relation between a Mendelian character and a chromosome, if such 

 relation exists. The investigation cannot be regarded as completed, 

 but in the account which follows of the results obtained, it will be seen 

 that the hope of identifying a chromosome as the bearer of a hereditary 

 character has not been fulfilled, although other phenomena of consider- 

 able interest have been observed. 



' Evolution Committu Roy. Soc. Report, it, 1908, p. 53. 

 Joarn. of Gen. i 18 



