152 THE SCOTTISH NATURALIST 



a time — early August — just too late to obtain unhatched 

 eggs and, consequently, there was no opportunity of enquiring 

 fully into the egg stage. 



The egg-slits or egg pockets were situated just below the 

 leaf-base and varied from fourteen to twenty-two in number, 

 seven to eleven on each side of the petiole. The incision 

 which was made on the side of the leaf-stalk from the upper 

 surface was oval in shape and the egg lay in a small pocket 

 resembling a minute tobacco-pouch (Fig. i). 



Egg. — The one egg which was found unhatched was 

 elongate, sac-like, oval, and of a yellow colour. It was 



Rtf- 



FiG. 2. — Damage by Younger Caterpillars. (Underside of leaf.) 



attached to the pocket in which it lay and measured from 

 0-5 to 0-75 mm. in length. 



T/ie Lai'V(S, which were collected, were reared in cages 

 in the laboratory on poplar leaves. The two or three 

 individuals of Croesus septentriojtalis, Leach, died, and so 

 attention was confined entirely to Trichiocampus vzminalis, 

 Fall. The young larvae, which were greenish-white in colour 

 with brown heads, fed socially in serried ranks on the under- 

 side of the lamina of the leaf. The epidermis alone was 

 eaten, the result being that the leaf was skeletonised and the 

 veins left intact (Fig. 2). It was noticed that after the third 

 month, in the fourth instar, in addition to the general 



