108 PLUSIA IOTA. 



on each side and at the mouth, which probably 

 accounts for the triangular specks on the egg. 



In a few days after feeding on Lamium purpureum 

 they became by degrees of a pale yellowish-green, and 

 from the 1st of August their food was changed to 

 Lamium album, and by the 1st of September they 

 measured three-eighths of an inch in length, and by the 

 16th half an inch in length, and were already hiber- 

 nating. They were bright yellowish-green in colour, 

 with slightly darker green dorsal stripe edged with a 

 whitish-yellow line, followed closely by another such 

 line, and the subdorsal line similar ; the spiracular line 

 of the same colour, a trifle thicker and more distinct, 

 the wart-like tubercles whitish and shining, each with 

 a dark brown hair. 



During the winter they moved but little from the 

 positions taken up on the roof of their cage, but in 

 January, 1875, they crawled about, and even ate a 

 little of Lamium purpureum. This they repeated at 

 intervals during March. In April they began to 

 moult and feed regularly at short periods, eating cow- 

 parsley, honeysuckle, and Lamium album. They 

 attained their full growth about the 17th of May, 

 when they measured from an inch and three-eighths 

 to an inch and a half in length, tapering gradually 

 from the eighth segment to the fourth, from thence 

 rapidly to the head, which is narrower than the second 

 segment and rather flattened. The two hinder seg- 

 ments are very little tapered. The twelfth slopes 

 downwards from the middle rather abruptly towards 

 the rounded anal tip. From the tenth forwards the 

 segments are plump in the middle, and well-defined. 

 Its colour is a pale and lively, or brilliant yellow-green, 

 deepest in tint on the sides and belly, where it appears 

 velvety. The head is rather the darkest green, 

 broadly marked with black on the side of each cheek, 

 from the mouth, which circumscribes the top of each 

 lobe on the crown with a fine black edging. The 

 triangular piece of the face is finely edged with black, 



