I70 STRANGE DWELLINGS. 



The handsome Oak Egger Moth {Gasiropacha quercus) 

 affords another example of the pensile cocoon. Of these insects 

 also I have had great numbers ; and some specimens of the 

 moth, chrysalis, and cocoon are now before me, the cocoon un- 

 changed by the eighteen years which have elapsed since it was 

 made, but the moth sadly faded, after the manner of its kind 

 when exposed to the action of light. 



Large as is the caterpillar of the Oak Egger moth, it is con- 

 tracted into a comparatively small chrysalis when it assumes 

 the pupal state, and makes a cocoon which only allows enough 

 space for the pupa and the cast larval skin. The form of the 

 cocoon is egg-shaped, whence the name of Oak Egger, and its 

 substance is rather peculiar, being thin, hard, and rather brittle 

 when quite dry. Externally it is surrounded by a loose layer 

 of silken threads, by means of which it is attached to the plant 

 on v/hich it hangs ; but the cocoon itself is smooth, very much 

 the colour of half-charred paper, and in spite of its brittleness is 

 possessed of some elasticity. 



There is a smaller insect, popularly called the Little Egger 

 Moth {Eriogaster la?iestris), which spins a cocoon of a similar 

 structure, except that the walls are of even harder and more 

 uniform texture, scarcely larger than a wren's egg, and of a 

 substance which looks almost as if it were made of the same 

 material as the egg. When broken, it is found to be even more 

 brittle than that of the larger insect. Owing, in all probability, 

 to the exceeding closeness of the structure, which would exclude 

 air from the inhabitant, it is perforated with one or two very 

 tiny and very circular holes, which look just as if some one had 

 been trying to kill the insect by piercing the cocoon with a fine 

 needle or pin. 



Even from the outside these perforations are visible, but they 

 are much more evident when the cocoon is opened. The ob- 

 ject of these holes is, however, conjectural, and it would be a 

 useful experiment to stop them with wax, in order to see whether 

 the inclosed insect could be developed when the air was thus 

 excluded, I believe that there are none of these holes in the 



