Manchester Memoirs, Vol. I. (1906), No. 6. 17 



somatic host which lodges them. This fact is interesting 

 in the light of Gaskell's (37) recent paper in which he 

 regards the adult individual as a neural syncytium holding 

 in its meshes the germ cells, and others, unconnected with 

 the nervous system. Petrunkewitsch's observatious re- 

 quire confirmation before they can be finally accepted. 



The fate of the polar bodies has not been traced in 

 any other cases except by Silvestri in Litoniastix where 

 they develop into an embryonic investment, which I 

 suggested might be the fate of the polar bodies oi Encyrtiis 

 and Polygnotus. In the majority of cases they simply 

 become resolved into a number of chromosomes and 

 disintegrate. 



Determination of Sex. 



The desire on the part of some writers to treat the 

 sex character as being of the same category as somatic 

 characters, which include secondary sexual characters, 

 seems to me to be quite unjustifiable. Sex has a much 

 more fundamental significance than have somatic 

 characters. In the sexes themselves, the essential differ- 

 ence between the male and female consists in the fact 

 that they produce different kinds of reproductive cells. 

 All other differences — that is, somatic differences, are 

 secondary and subservient to the act of reproduction and 

 the development of the individual. 



At the present stage of our knowledge, I think that 

 Castle's (21) attempt to fit in the facts of maturation with 

 the Mendelian principles of dominance and segregation 

 is premature. Comparatively few cases of partheno- 

 genesis in insects have been worked out with a view to 

 studying the maturation of the ova, but of the few cases 

 which we already know, a fairly large percentage would 



