THE GENUS ACRONYCTA AND ITS ALLIES. 29 



leporina on birch, certainly I have never taken anything else 

 for leporina, though I have not unfrequently found the full- 

 grown larva at rest on birch. My difficulty in accepting Mr. 

 Poulton's hypothesis is, that the protection on alder is cer- 

 tainly by a very different resemblance, whilst on birch, I can 

 call to mind no cocoon that it is at all like ; indeed the only 

 one at the right season is that of Ennomos tiliaria, to which 

 leporina larva bears no resemblance. An Orgyia antiqua cocoon 

 might occur, but is not common on birch, nor has it the right 

 tint. In any case leporina presents a marked instance of a 

 dimorphous larva, each form being suited to different circum- 

 stances and almost certainly for purposes of concealment. 



The dimorphism of the adult larva wants further investiga- 

 tion as to its geographical distribution, and I shall be glad to 

 hear, from as many localities as possible, as to which form is 

 found, and under what circumstances. As far as my present 

 nformation goes, I regard the white as a southern, the yellow 

 as a northern form, but I also associate the white with alder, 

 the yellow with birch. This may result from the circumstance 

 that here I usually capture the white form on alder, rarely on 

 birch. In Scotland I used always to take the yellow form 

 freely on birch, rarely on alder. I do not know that alder is 

 more common in the south and birch in the north, as an 

 actual botanical fact, both being fairly common everywhere, 

 but certainly they have that relationship in the habitats of 

 leporina in which I have hunted. As a basis to elicit further 

 information I may say, that somewhere about Cheshire or 

 Lancashire the white form gives place to the yellow. Does 

 the white extend further north on the east coast ? What form 

 occurs in Wales and Ireland ? Especially information would 

 be interesting from any locality where both forms occur with 

 equal frequency. The moths from the two forms cross readily, 

 and, in one brood at least, the resulting larvae were the most 

 richly coloured I have seen, and preserved the black tufts more 

 freely into the last skin than any others I have met with. 



{To be continued.) 



Dr. Chapman's query, re the forms of the larvae of this 

 species, which was published in the last number {ante. p. ig), 

 should have been inserted with this part of the paper. — Ed.^ 



