Appendix. 1 49 



EXPERIMENTS WITH .GRAPTA INTERROGATION^/ 



{Communicated by Mr. W. H EDWARDS, November i$th, 1879.] 



The experiments with this species were made in June, 

 1879, on pupse from eggs laid by the summer form 

 Umbrosa of the second brood of the year, and obtained 

 by confining a female in a bag on a stem of hop. As 

 the pupae formed, and at intervals of from six to twenty- 

 four hours after pupation (by which time all the older 

 ones had fully hardened), they were placed in the ice- 

 box. In making this experiment Mr. Edwards had 

 three objects in view. ist. To see whether it was essen- 

 tial that the exposure should take place immediately 

 after pupation, in order to effect any change. 2ndly. 

 To see how short a period would suffice to bring about 

 any change. 3rdly. Whether exposing the summer 

 pupse would bring about a change in the form of the 

 resulting butterfly. Inasmuch as breeding from the egg 

 of Umbrosa, in June, in a former year, 7 gave both Um- 

 brosa (n) and Fabricii (6), the butterflies from the eggs 

 obtained, if left to nature, might be expected to be of 

 both forms. The last or fourth brood of the year having 

 been found up to the present time to be Fabricii, and the 

 ist brood of the spring, raised from eggs of Fabricii (laid 

 in confinement), having been found to be wholly Um- 

 brosa, the latter is probably the summer and Fabricii the 

 winter form. The two intervening broods, i. e. the 2nd 

 and 3rd, have yielded both forms. This species hiber- 

 nates in the imago state. 



After the pupse had been in the ice-box fourteen days 

 they were all removed but 5, which were left in six days 

 longer. Several were dead at the end of fourteen days. 

 The temperature most of the time was i 2 9 R. ; but for 



7 See Canad. Ent, vol. ix. p. 69. 



