12 BBITISH BUTTERFLIES AND MOTHS 



some neighbouring object, fasten their hind legs in it,, 

 and hang with the head downwards and the anterior 

 portion of the body rather curved. In a couple of days 

 the skin cracks, and is pushed upwards towards the tail, 

 and the much shorter, stouter-looking object which 

 remains is the chrysalis. In two or three weeks the 

 colouring beneath the thin wing-cases of the chrysalis 

 clearly shows that the butterfly is nearly developed, and, 

 the chrysalis skin cracking, the butterfly creeps out, 

 and, having expanded and dried its wings, flits before 

 us along the road, settling from time to time either on 

 the ground or amongst the herbage. 



Thus, in the examples already given, we have in- 

 stances of butterflies which pass the winter in the pupa 

 state, or as hibernating perfect insects, or in the larva 

 state. 



We turn now to a consideration of the metamorphoses 

 of the common Blue Butterfly (Polyommatus Alexis). 

 If the parent butterfly deposits her eggs in September, 

 the larvas soon hatch, but remain small through the 

 winter, and do not begin to feed up till the spring. 

 The eggs are deposited on the leaves of clover and bird's- 

 foot trefoil (Lotus corniculatus), and if in the month of 

 April we stoop down and examine these plants, we may 

 probably meet with a curious woodlouse- shaped creature, 

 about half an inch in length, of a rather dark green, 

 clothed with short brown hairs, giving it a velvety ap- 

 pearance; along the sides are some short oblique blackish 

 streaks ; the head and legs are placed completely under 

 the body, and quite out of sight : this would be the 

 larva of our common Blue Butterfly. Towards the 

 end of April it is full fed, and spins some silk, in which 

 it fastens its hind legs, and then passes a silken belt 



