336 THE ENTOMOLOGIST. 



At these temperatures it was therefore to be expected that the 

 captures of the 5th and 6th September would not correspond 

 with my " high temperature forms at 80° to 90°, but ivould 

 correspond more nearly with some of my lower temperature 

 forms, those, for example, of the class at about 70°, or those " at 

 about 56° to 58°." And this I gather from Mr. Frohawk's 

 description of them is what they do. His description is as 

 follows : — " All that I examined were of brilliant colouring, the 

 copper being rich and bright, and the black deep ; in most cases 

 they resembled Mr. Merrifield's low temperature forms." For 

 comparison with this, I will give my description of the general 

 colouring of some of my " low temperature " forms. Of those at 

 a temperature averaging about 70° I say (p. 63), " these are 

 noticeably dif event [i.e., from the duskier ones at 80° or upwards] , 

 the colours are more intense, the dark parts blacker, the coppery 

 parts more vivid." The other classes (at about 58° and 56° re- 

 spectively), are described by me as showing but " a slight further 

 increase [i. e., as compared with those at 70°] in the brightness 

 of the coppery parts." Mr. Frohawk does not say which of my 

 lower temperature forms his captures most resembled ; nor 

 indeed do I gather that they have been compared side by side 

 with mine, which are at present deposited at the British (Nntural 

 History) Museum, a comparison which should certainly be made 

 to ensure accuracy ; and even then it should be bornei n mind 

 that out of the hundreds captured it is probably the brightest 

 of their sort that would have been preserved, whereas the whole 

 of mine were preserved and exhibited. But I think I shall be 

 right in assuming that Mr. Frohawk does not mean that his 

 resembled my loivest temperature forms (i.e., 47° and under), for 

 these are especially remarkable for (1) the breadth of the copper 

 band on the hind wings, and (2) the fact that the coppery scales 

 are often prolonged along the nervures from the band towards 

 the bases of the wings, whereas Mr. Frohawk does not mention 

 a broad band as any characteristic feature, and speaks of the 

 second feature as having been found on only one of his hundreds 

 of captures. 



I have admitted, and do most fully contend for, the impossi- 

 bility of saying, with any near approach to accuracy, to what 

 temperature the pupae of the captured C. phloeas were exposed. 

 But that is a reason for not assuming that their appearance is 

 conti'adictory to my conclusions from experiments where the 

 exact temperature can be ascertained. And before accepting the 

 view that they are thus contradictory, — a view grounded on 

 observations in the open field, where the conditions for exactness 

 do not exist, — I think it would have to be shown how the results 

 obtained by me under circumstances admitting of exact obser- 

 vation are to be explained. 



Besides, there is in this case another formidable fact to be 



