Appendix. 123 



All these were sharply impressed with the characters 

 of the winter form, the females all strongly yellow on the 

 upper side, the males pure white ; on the under side a 

 strong black dusting on the hind wings, particularly on 

 the discoidal ceil. One pupa did not emerge in the 

 hothouse, but hibernated, and gave in a heated room on 

 January 2Oth, 1873, a female, also of the winter form. 



14. Females of Pieris Napi, captured on 2/th 28th 

 April, 1872, laid eggs on Sisymbrium Alliaria. The 

 larvae bred from these pupated on May 28th to June 7th. 

 The pupae, shortly after transformation, were placed on 

 ice, where they remained till Sept. nth (three months). 

 Transferred to the hothouse on October 3rd, they pro- 

 duced, up to October 2oth, 60 butterflies, all with the 

 sharply-defined characters of the winter form. The re- 

 maining pupae hibernated in a room, and produced : 



On the 28th of April, 3 males, 6 females. 



4th of May, I female. 



1 2th 4 males. 



1 5th i male, I female. 



1 6th i male. 



1 8th i male, I female. 



1 9th i female. 



2Oth 2 males, i female. 



23rd 2 males. 



26th i male. 



29th i female. 



3rd of June, 3 females. 



6th i female. 



9th i female. 



2 ist i female. 



2nd of July, I female. 



Total . . 15 males, 19 females. 

 15. Several butterflies from Exp. 14, which emerged 

 in May, 1873, were placed in a capacious breeding- 



