2 THE ENTOMOLOGIST S RECORD. 



not SO industrious in taking full notes as not to leave much to 

 be desired. 



I may refer here to a paper in the Transactions of the Ento- 

 vwlogical Society for 1879, by Mr. A. G. Butler, which pro- 

 pounded such extraordinary ideas that I felt it was necessary 

 that further research should confirm or refute them, and I may 

 say at once that it proves to be a case in which one's natural 

 suspicion is well founded, and not the result of mere prejudice 

 and habit. 



Although the genus Acronycta, as represented by our British 

 species, naturally divides itself into three very distinct and 

 well-marked groups, and though some species, hitherto placed 

 in separate genera, such as venosa already referred to, seem 

 closer to one of these groups than these groups are to each 

 other, the genus, without precisely defining its limits at pre- 

 sent, is very distinct from other families of the NocTU^ and 

 from any group of Bombyces. Some of the outlying species 

 that have at different times been referred to in this group, 

 present some difficulty in deciding whether they really belong 

 to the AcRONYCTiD.^ or not, and with what other groups they 

 have more or less affinity — such species are orion, coryli, 

 coeruleocephala. But leaving these for the moment on one side, 

 and confining our attention to the species more typical of the 

 genus and group, we find certain points of affinity throughout 

 all their stages that bind them together and distinguish them 

 from other families. 



The Q.^'g is low dome shaped, that is, it consists of a 

 segment of a sphere, always less, usually much less, than a 

 hemisphere, lying on its fiat side, and ribbed from the summit 

 to the circumference in a way that I have learned to regard as 

 characteristic of NocTU^, though I am not able to distinguish 

 it by description from that met with in other groups ; the 

 typical NocTUA &gg, though ribbed in this manner, is usually 

 more or less spherical. 



The most characteristic stage is the newly-hatched larva. 

 It tends to have certain segments pale and others dark, but in 

 all cases the eleventh segment is paler, smaller, and " weaker" 

 than the rest ; it is occasionally a little broader than the others, 

 but it is always lower and flatter, and its tubercles and bristles 

 are smaller and less developed. This relative development of 

 the eleventh segment persists in many species throughout the 

 life of the larvae, even to the full-grown period ; in alni, for 

 instance, this segment has no clavate hairs. 



