THE GENUS ACRONYCTA AND ITS ALLIES. 75 



only species that I have observed make fairly successful at- 

 tempts to be double-brooded, but I fancy, in a state of nature, 

 they are usually unsuccessful ; that is, that the specimens that 

 emerge in the autumn do not do so early enough to give their 

 progeny time to certainly feed up before winter. The Brst 

 brood of tridens that I reared in 1886 divided itself into two 

 portions, one of which came out at the beginning of August, 

 the other remained over till the following year. This expe- 

 rience has not occurred to me since, nor have I ever had an 

 autumnal emergence of psi. Ruinicis very commonly affords 

 an autumnal specimen or two, and it not unfrequently puts in 

 an appearance at sugar in August, in the south of England. 



Sundry species occasionally remain two or more 3'ears in the 

 pupa state. I never had any of the Viminia group do so 

 successfully. Psi and tridens have presented two or three 

 pupae that remained alive till the following year, but failed to 

 emerge. Alni, strigosa, and aceris have never shown any 

 tendency of this sort ; but with megacepliala it is quite frequent, 

 half of a brood sometimes going over to the second year, and 

 emerging as satisfactorily as in the first year, and some take a 

 third winter in the pupa state. Leporina also goes over a second 

 year easily and successfully, but in a smaller proportion of 

 cases, and rarely takes a third year. Ligustri remains over 

 sometimes, but has so far in my hands failed to emerge. 



The Q.^^ of ani'iconm is laid in the imbricated manner 

 characteristic of Viminia, but, like my rices, in smaller groups 

 than in the others, and with more frequent single specimens. It 

 is I.I mm. in diameter, and about two-sevenths of this in 

 height, the ribs are fifty-seven to sixty in number, and are 

 waved or crenulated as in the other species ; pale creamy 

 when first laid, it passes into a rich reddish chocolate brown, 

 with numerous white or creamy spots, which are more regular 

 and distinct in outline and distribution than the pale markings 

 are in the other species of Viminia. In several instances my 

 drawings of the eggs of Acronycta have not been taken at the 

 best point in the development of the markings, which, after 

 reaching their best and most perfect stage, rapidly became 

 confused and obscure again as the young larva within matures. 



In this clearness and distinctness of the rounded white spots 

 this &^^ comes nearer, in general aspect, to that of alni than 

 do any of the other species of Viminia, but the spots are 

 smaller and more numerous than in alni, the outer or marginal 

 set forming a tolerably complete ring of small spots ; the 



