STRUCTURE OF COCOON OF EMPEROR MOTH. 9 



is constructed mth an elastic aperture, preventing the en- 

 trance of enemies, but allowing exit to the inhabitant; 

 the numberless progeny of the aphis, the powerful flight 

 of the locust, the leap of the elater and grasshopper, 

 the brilhant Ught of the glow-worm, the instinct of the 

 sexton-beetles (Necrophorus), the mottled jacket of the 

 lai-va of the clothes-moth, formed of diflferent coloured 

 wool, or the excrementitious covering of the larva of the 

 Cassida, the frothy abode of the Cercopis, the abandoned 



Cassida viridis in its different states. 



shell inhabited by the hermit crab, and the extraordinary 

 gall residences of the Cynipidce : all these, and a thousand 

 other not less interesting circumstances exhibited, and to 



of loosely attached longitudinal threads, converging like so many bristles 

 to a blunt point, in the middle of which is a circular opening, through 



which the moth makes its es- 

 cape, the threads readily yield- 

 ing to pressure from within, and 

 acting somewhat upon the prin- 

 ciple of the wires of the opening 

 to a rat-trap, or the willow cricks 

 of an eel-trunk. In order, how- 

 ever, to guard against the danger 

 which might arise from the open- 

 ing permitting the ingress of ich- 

 neumons or other enemies, the 

 caterpillar constructs within the 

 funnel-shaped mouth a second 

 funnel formed of a similar series of threads converging to a point, without 

 the smallest opening being left, and its arched structure rendering it im- 



Chrysalis and section of the cocoon of the 

 ))eror Moth, showing, a. The internal dome — 

 0, The external aperture. 



