10 Female Families^ in Abraxas 



2. In some cases unisexual families have been produced when both 

 pai-ents belonged to bisexual families descended directly from unisexual 

 families. In other cases such matings have given families with gi-eat 

 preponderance of females, but some males. 



3. About half the females of a unisexual family have only female 

 offspring. Infertility in such families is frequent. 



4. The normal number of chromosomes in both sexes, whether 

 gross tdariuta or lacticolor, is 56. Females of unisexual families, how- 

 ever, have often, and probably always, only 55. 



5. Females of bisexual familie.s, descended directly from unisexual 

 families, have in some cases 56, probably in others 55 chromosomes. 

 As far as is known, males always have 56. 



6. It is suggested that the elimination of one chromosome may be 

 correlated with the elimination of the grossuluriata factor. The 

 investigation is not yet far enough advanced to give definite evidence 

 of the relation between the behaviour of the chromosomes and the 

 phenomena of sex-determination in this species. 



