JOURNAL OF VARIATION 
No. 6. VoL. II. 
August 15 th, 1891 , 
THE GENUS ACRONYCTA AND ITS ALLIES. 
By Dr. T. A. CHAPMAN. 
{Co 7 itinned from page 77.) 
CROl^YCTA {Cuspidia) ahii. — Alni seems to come 
nearer to psi, tridens, and strigosa than the remaining 
species we have still to examine, though it is dis- 
tinguished from all the rest of the genus by the 
curious neck which marks off the anal armature of the pupa ; 
this seems correlated with its manner of pupating, which is 
very like that of leporina. In alni the elaboration for providing 
abundant entanglement in the silk, of the end of the cocoon, 
is found in this curious groove, the spines remaining of the 
same simple type as in tridens ; whilst in leporma it is achieved 
by an abundant multiplication of the spines and their curving 
into very efficient hooks. 
The egg is laid at the end of June or beginning of July, 
always solitarily, I conjecture on the upper side of the leaf, 
though in captivity it lays them on either side. I recently had 
an opportunity of observing psi deposit her eggs when in 
freedom. The moth came from some little distance, laid two 
eggs a quarter of an inch apart on the under side of a haw- 
thorn leaf, and then flew off out of sight. I have already 
recorded finding an egg of psi on the upper side of an oak leaf. 
Psi as a young larva affects either side of the leaf, but as alni 
lives on the upper side, the eggs are probably laid there. 
When first laid the egg (PI. VIII., fig. 6) is nearly as colour- 
less as that of psi, but soon assumes some coloration, and in 
about three days, reaches its proper tint. For twenty-four 
hours before hatching it becomes much darker, with the black 
head of the larva occupying the summit. 
In form the egg is of typical Acronycta shape ; the diameter 
