RURALIS BETULJE. 297 



anterior margin of which projects beyond the head ; the segments are 

 deeply and distinctly divided, so much so as to give the back, when 

 viewed sideways, a serrated appearance ; the dilated sides and dorsal 

 keel are each garnished with a fringe of stiff hairs ; this fringe is 

 double on the dorsal keel, but single on the lateral dilation ; on the 

 former, each hair is curved into the segment of a circle, and its end is 

 directed backwards; on the margin, each hair is also curved, but more 

 slightly, and its end is directed downwards. The colour of the head 

 is brown, and its surface very glabrous ; that of the body apple-green, 

 with four narrow, longitudinal, whitish stripes, and two oblique lines 

 of the same hue on each side of each segment; two of the longitudinal 

 stripes are dorsal, they are distant on the pro- and mesothorax, 

 gradually approach on the metathorax and 1st abdominal segment, 

 and thence run parallel to the 9th abdominal segment ; the other stripes 

 are lateral, and, running completely round the margin of all the segments 

 of the body, unite on the prothorax and 9th abdominal segment; on the 

 prothorax are two short pale longitudinal lines, side by side ; the 

 ventral surface, including the legs and claspers, is pale, semi-trans- 

 parent, glaucous-green, with a vague medioventral smoke-coloured 

 stripe, probably due to the presence of food in the intestinal canal 

 (Newman). 



Colour change preceding pupation. — The full green colour was 

 observed on the evening of July 5th; the specimen was not seen again 

 till the morning of July 8th. The ground colour is now of a dull purplish 

 or reddish-mauve hue, with a slightly greenish tinge along the lower 

 area of the sides, above the lateral flange. This area is bounded by a 

 very distinct purplish spiracular line, which extends downwards, and 

 reaches the resting-margin of the larva at the 8th abdominal segment. 

 The whole of the hinder abdominal segments distinctly more purple 

 than the rest of the body, the thoracic area, front slope, and apices of 

 the dorsal serrations, being still of a somewhat purplish-green tint. 

 The oblique lines, from the bases of the dorsal humps to the spiracu- 

 lar line, quite white ; the lateral edges of the dorsal serrations also 

 white ; as also is the marginal edge of the subspiracular flange, 

 remarkably so on that part belonging to the 8th, 9th, and 10th abdo- 

 minal segments. The ventral area (including all that below the 

 subspiracular flange) of a rather dull greenish tint. Another com- 

 menced to change colour on July 13th. The next day it was of a 

 deep mauve- or purplish-red colour, almost unicolorous in tint, except 

 that the edges of the dorsal ridge and marginal flange were pale and 

 shiny. The oblique lines now only show faintly, their tint being almost 

 identical with that of the ground colour, the lower series being almost 

 obsolete. The spiracles are slightly paler than the ground tint. 

 Prideaux observes that, immediately before the final larval skin is cast, 

 the larva is rather brightly coloured, the colours being a pinkish- 

 mauve, with the dorsal and lateral skin-ridges translucent green. 



Larva in quiescent stage preceding pupation. — When in the 

 quiescent stage preceding pupation, the dorsum is regularly arched 

 from the prothorax to the anus. The head is quite hidden ventrally, 

 and the venter is pressed closely down to the surface, on which it has 

 spun a strong silken web ; the subspiracular flange, however, is well 

 up, and the area between this and the base of the prolegs well-exposed. 

 The apex of the 3rd abdominal segment is the highest point of the 



