"^722 Inaecls. 



tlieir deep orange colour. In the middle of the month of July, 1844, 

 I found some larvae on a poplar at Zwamnierdam ; they were just out 

 of the eggs, which were enclosed in the leaf-stalk. I was surprised 

 at making this discovery at that particular season, as in the previous 

 week I had seen perfect insects of the same species appear from the 

 cocoons in my house. Probably the female by whom the eggs were 

 deposited in the leaf-stalk had already appeared in the month of May, 

 and it may be that the temperature of my room, which faced the 

 north, had had some effect on the development of the insects. 



The eggs were deposited on either side of the leaf-stalk of the 

 poplar. The petiole was swollen on both sides, over and partially 

 covering the eggs. I counted eight eggs on one side and ten on the 

 other. The young larvae, which were green with black heads, dis- 

 posed themselves in a curved line on the under side of the leaf, the 

 head being turned towards the point of the leaf; they consumed the 

 lower epidermis and parenchyma only. After the second moult the 

 yellow colour began to show itself on the first and penultimate seg- 

 ments, and the black spots became visible. Fig. 1 on plate 10 repre- 

 sents the larva after its third moult ; the head is then pitchy brown ; 

 the body sea-green, excepting the first and penultimate segments, 

 which are yellowish orange. A deeper green stripe runs along the 

 back, and on the sides are to be seen black spots having the same 

 position as in the 'full-grown larva, which is represented at our fig. 2, 

 This latter is cylindrical, though larger round at the head than at the 

 tail, and generally of a beautiful orange colour, but which in some 

 individuals is tinged with green, especially in the middle of the dor- 

 sum. Tlie skin is entirely covered with soft white hairs, which, when 

 submitted to the microscope, appear to be spinous. The head is 

 compressed anteriorly, the groundcolour is pale. brown, but, being 

 covered with hundreds of minute black points, the whole head has 

 the appearance of being black. The jaws are yellowish. The labrurn 

 IS heart-shaped, notched at the anterior margin ; the mandibles are 

 much curved, and provided with one large tooth and three small ones ; 

 the maxilltB consist of two parts, — one broad and membranous, to 

 which is attached the five-jointed palpus, and having first two and 

 then seven long narrow, teeth or projections ; the other part of the 

 maxilla is narrow and corneous. The labium is broad, wavy at the 

 margin, and has two three-jointed palpi. The prothorax and the two 

 last segments of the body have a round or sometimes square spot on 

 either side ; on the other segments is a similar spot, only larger and 

 having a smaller sj)ot below it ; above the anus is a pretty large cen- 



