1 64 LEPIDOPTERA. 



occasionally found, whicli, though rare, appears to exist as a 

 recurrent variety ; it is devoid of the white scales, even the 

 base of the fore wings being very dark ; and having more 

 than the basal half of the hind wings occupied by a smoky- 

 brown cloud. Another phase of variation has incidentally 

 been pointed out above, in the presence or absence of a yellow 

 discal spot and a yellow or white blotch at the anal angle. 

 On the wing in June and July. 



Laeva rather soft and limp ; long, cylindrical, with the 

 head larger, but no humps. Head round, black, with the 

 lobes outlined in yellow ; body downy, from a covering of 

 small whitish hairs ; yellow, clouded with grey on the back of 

 each segment, or when quite full grown of a more greenish 

 yellow; dorsal stripe rather broad, dull black, interrupted 

 at each segmental division ; subdorsal line grey, slender ; 

 beneath it two similar lines, all three interrupted in the same 

 manner ; spiracles black ; legs black or greyish-black ; prolegs 

 blackish. Larger whitish hairs project over the head. 



August and September on elm, lime, willow, sallow, oak, 

 birch, beech, alder, sycamore. It has been found even on 

 laurel and on Tropcv,olum majus, and is far from 'particular in 

 its choice of food, though in the suburbs of London, where it 

 is abundant, lime appears to be chiefly selected. The eggs 

 are deposited in clusters and the young larvae remain together 

 in companies, feeding side by side so as to clear leaf after leaf, 

 and render their presence conspicuous by stripping the por- 

 tion of a branch on which they reside. When, however, the 

 higher portion of the branch is cleared the whole company 

 suddenly leaves it and takes possession of another branch, 

 usually high up the tree, stripping it in a similar manner. 

 Each company seems to shift its position in this manner 

 three times at least. When not feeding, the larvae crowd 

 together into a solid bunch on one of the twigs, their ex- 

 tremities protruding from the cluster and giving it a ragged 

 look very like a leaf which has been eaten, leaving the 



