Sept. 1S91. 



PSTCHE. 



149 



The results obtained appear also to indi- 

 cate that probably some local climatic vari- 

 eties, and even seasonal varieties, may be 

 found to be, in part at least, temperature 

 forms of the individual ; and, looked at from 

 this point of view they appear to me to lend 

 some support to Lord Walsingham's theory 

 as to the advantages derived by an insect in a 

 cold region from being of a dark color, for 

 they show that, if that is an advantage, it is 

 one that can be acquired, not only by a race 

 for use in a cold locality, but by individuals 

 for use in a cold season. I think it is quite 

 clear that if a cool week supervened in south- 

 ern England between the beginning and the 

 middle of July, or a hot week in the middle 

 of April, at either of which times many of the 

 pupae of illustraria would be in what I have 

 called the penultimate pupal stage, most of 

 these insects which it found in that stage 

 would have their coloring affected. It would 

 appear that even two or three hot days, if 

 they came exactly at the right period, would 

 be enough for the purpose; and I need 

 hardly observe that it is very unlikely that 

 these are the only species that would be so 

 affected. 



There is another general suggestion which 

 I venture to make in concluding. If Prof. 

 Weismann's theory is accepted, that the exist- 

 ing forms of most European and some North 

 American Lepidoptera have come to us from 

 a glacial period or climate, and that icing the 

 pupa causes the insect to "throwback" to its 

 earlier form, then experiments of the kind 

 tried on the pupae might assist us in tracing 

 the evolution of the markings on the wings 

 of some of the most highly developed forms. 



In a postscript he adds : — 



I am now able to add that the coloring of 

 the spring emergence of illustraria is as much, 

 or nearly as much, affected by temperature 

 during the penultimate pupal period as is that 

 of the summer emergence. This has been 

 established in case of three different broods, 

 portions of each having been subjected to 

 temperatures of 6o° and 8o° respectively; the 



latter often in coloring very closely approach 

 the light chestnut-orange summer type. • This 

 is interesting in reference to Prof. Weis- 

 mann's theory, that in cases of this kind, the 

 moth from the summer pupa can be caused 

 to resemble that from the winter pupa, but 

 not vice versa, as it shows that either form is 

 equally ready, oti the suitable temperature 

 stimulus being applied, to assume the char- 

 acteristic appearance of the other, so far as 

 coloring is concerned. In other respects my 

 observations are in accord with that theory. 

 Thus, I have never been able to cause the 

 moth from the winter pupa to take the mark- 

 ings proper to the moth from the summer 

 pupa, whereas the moth from the summer 

 pupa can be made in markings to resemble 

 almost exactly that from the winter pupa; 

 nor have I been able to cause the moth from 

 the winter pupa to emerge in a period 

 approaching in brevity that of the summer 

 pupa; indeed, in the great majority of cases, 

 the early and continued exposure of the win- 

 ter pupa to a temperature of So°, or even 6o c , 

 caused its death. 



Some Abnormal Larvae. — One larva of 

 Thyreus abbotii had a single, thick, stiff 

 hairlike bristle, arising from the tip of the 

 caudal tubercle, all through the third moult, 

 the second and fourth moults being normal. 

 Another larva of T. abbotii kept the 

 whitish green coloring of the early moults 

 until it pupated, the only change of marking 

 being a vague lateral line slightly darker 

 than the body, and the usual changes of anal 

 tubercle. Caroline G. Soule. 



Another Deidamia inscripta.— On July 

 13th on Ampelopsis veitc/u'i, I found a larva 

 so like Everyx myron that I put it away as 

 such, though it had no purplish spots on the 

 back. It differed from last year's specimen 

 in having faint yellow obliques, and in hav- 

 ing the yellow lines from the head extending 

 nearly to the eleventh segment. The pupa, 

 formed on July 17th, was like that of last 

 year, except that it lacked the spur near the 



