LEPIDOPTEROLOGIE COMPAREE 479 



have produced, as femaleness is dominant, females of the 

 type Q Q and of the type cfç but maies only of the form cfcf- 



Or diagrammatically thus : 



cfQ X cfg 



QQ QCf CfQ Cfcf 



"~~ "^ ~ ^ maie. 



ail female. 



In other words, we should have females in the proportion 

 of 3 : I, and this is in direct accord with expérimental results. 

 for females are obtained in excess; exact figures, however, are not 

 available, because the female larvœ take longer to feed up and, 

 as the last larvas are always attacked by a deadly infections 

 disease, there is thus a greater mortdlity amongst them; this tends 

 to restore the balance of the sexes. 



In two cases the following results were noted : 



1. Zonaria cf x pomonaria Q yielded 43 pupas giving 28 Qs: 

 15 cf s. 



2. Zonaria cT x hirtaria Q yielded 71 pupae giving 51 Qs : 

 20 cf s. 



Présuma bly, to judge from Mr. Mera's duplicates, zonaria cf x 

 lapponaria cf gives a similar excess of females. 



Turn now to the cross hirtaria (S x zonaria Q ; the product of 

 this ought to be of the nature c^" Cf as is the case. The same ought 

 to hold good with crosses between any two species, one selected 

 from each of the two groups, this we find is in accord with 

 observed facts. 



A cross between two species of the same group, ought to give 

 us maies of the constitution cfcf. and females of the type cf Ç>, 

 in approximately equal numbers, and this was found to be the 



