it is no uncommon occurrence, to have a spell of cold weather, 

 accompanied by snow, even during the summer months. 

 These conditions are precisely those which Mr. Merrifield has 

 imitated by exposing the chrysalids of butterflies to cold for 

 a few days prior to the emergence of the imagines, and the 

 result has in many cases been similar, notably in Vanessa 

 polychloros. 



Melanism is a very large subject, and one on which the 

 materials for generalization are quite inadequate. It is 

 common both to vertebrates and invertebrates ; and the cause 

 which has produced a black Argynnis, or Apatura, is doubt- 

 less very different from that which produces blackness in a 

 horse, ox, dog, or cat. 



Melanism seems the very opposite of albinism ; and yet in 

 both phenomena there is an absence of colour, and in some 

 respects they, seem allied. I have known a pure black fowl 

 in one moult to change to pure white ; and one instance came 

 under my notice of a white peafowl chick moulting into an 

 unusually dark peacock of the variety nigripennis. I have 

 also known black ducks become almost white. 



It is singular that albinism should be so rare amongst 

 Lepidoptera. I have never taken but one albino moth, viz., 

 Eiibolia bipunctaria : pallid or xanthic forms are by no means 

 uncommon. 



Referring again to Mr. Merrifield's experiments, the most 

 interesting fact substantiated is the alteration of the pattern 

 of the markings of the imagines of the second emergence by 

 the application of cold to the pupae. 



In the case of Selenia illiistraria the moth of the spring is 

 not only very much darker than that of the summer emer- 

 gence, but the bars of the wings are of a different shape. In 

 the former, the exterior bar is more diagonal and somewhat 

 waved ; in the latter, the same bar is not placed in so 

 diagonal a position on the upper wings ; and it is also dis- 

 tinctly angulated at about one third of the breadth of the 

 wing from the costal margin. 



Mr. Merrifield has shown that by the application of cold to 

 the pupae, the imagines of the summer emergence are pro- 

 duced both in colour ana markings alike to those of the normal 

 spring emergence. Such an immediate response to an 

 alteration of temperature is one that could not have been 

 foretold, had not those valuable experiments been made. 



Dr.Weismann's theory w hich he applied to the horaeomorphic 

 butterfly Pieris napi, seems to be borne out by Mr. Merrifield's 

 experiments on the moth, that it is descended from a mono- 



