CHRYSOPHANUS SALUSTIUS. 173 
being also plainly visible as a small black spot near the apex ; 
at this point a circular hole is afterwards drilled in the shell, 
through which the enclosed larva finally makes its escape. 
These larve are very minute, at first measuring barely half a 
line in length, and their thickness does not exceed that of the 
finest cotton. A careful microscopic drawing was at once 
made of the caterpillar, and is here given; and the following 
peculiarities were noted. 
YOUNG LARVA OF CHRYSOPHANUS SALUSTIUS. 
The head is very small, of a dull brown colour, almost 
hidden above by the thoracic segments, which are considerably 
swollen, the rest gradually tapering off towards the anus, where 
they become slightly attenuated. The general colour of the 
larva is pale green, darker on the dorsal surface, where a pair 
of conspicuous black warts are situated, a long erect bristle 
standing up from each of these, and a number of smaller ones 
also taking their rise from the ventral and anterior portions of 
the insect. 
I was, of course, quite ignorant as to the food-plant of 
Chrysophanus salustius, but dock and sorrel naturally suggested 
themselves as the most likely from the two allied British species 
(Polyommatus dispar and P. phleas) feeding on these ; I accord- 
ingly tried the former plant, and was delighted, while watching 
one of the larva under the microscope, to see a dark green spot 
rapidly forming inside it, and, on removing the insect shortly 
afterwards I observed a minute circular hole eaten out of the 
parenchyma of the leaf. For about a week they progressed 
very well, only two deaths occurring during this period ; it was 
now evident that the first moult was taking place, as all feeding 
had ceased, and the larve assumed a very sickly appearance. 
Five died during the change, and one was accidentally killed, the 
number being thus reduced to eleven. I should here mention 
that the exuvie are not eaten by the larve after moulting. 
Circumstances compelling me to leave home at this time, it was 
