1 1 8 Appendix. 



3. Larvae found on the i/th June, 1869, were sorted 

 according to colour ; the yellow ones, with light brown 

 spines, produced, at the ordinary temperature, on 8th 

 I2th July, 13 butterflies, 12 of which showed the ordinary 

 Prorsa type, and one, a male, possessing more yellow 

 than fig. 3, PI. I., must be considered as a Porima 

 type. 



4. From caterpillars of the second generation, found 

 at the same time as those of Exp. 3, 30 pupae were 

 placed in the refrigerator (temperature 8 10 R.) on 

 June 25th. When the box was opened on August 3rd, 

 almost all had emerged, many being dead, and all, 

 without exception, were of the intermediate form 

 (Porima), although nearer the Prorsa than the Lev ana 

 type. 



5. A large number of caterpillars of the second genera- 

 tion, found at the same time, pupated, and were kept at 

 a high summer temperature. After a pupal period of 

 about 19 days, some 70 butterflies emerged from 28th 

 June to 5th July, all of the Prorsa form, with the excep- 

 tion of 5, which were strongly marked with yellow 

 (Porima). 



6. The 70 butterflies of the foregoing experiment were 

 placed in an enclosure 6 feet high, and 8 feet long, in 

 which, during warm weather, they freely swarmed on 

 flowers. Copulation was only once observed, and but 

 one female laid eggs on nettle on July 4th. At the 

 high summer temperature prevailing at the time, these 

 eggs produced butterflies after 30 31 days (third 

 generation). All were Prorsa, with more or less yellow ; 

 among 1 8 none were completely Porima. 



7. Young larvae of the fourth generation, found on the 

 8th of August, were reared in a hothouse (17 20 R.). 

 They pupated on 2ist 23rd August. Of these : 



A. 56 pupae were placed on ice (o 1 R.) for five 

 weeks, and then allowed to hibernate in a room 



