294 HOMES WITHOUT HANDS. 



Heaumur, who discovered these curious objects, found that when 

 the cocoon was detached from the branch and laid on the table it 

 sprang to a distance of several inches, probably because the in- 

 closed insect was able to bend itself and then suddenly straighten 

 the body. 



Reaumur believes that the Ichneumons which make these pen- 

 sile cocoons are parasitic on the processionary caterpillars, because 

 he found them plentiful near the nests of these insects. 



How the cocoons are made and suspended is quite a mystery. 

 Mr. Westwood offers a suggestion that, before changing into the 

 pupal state, the insect spins its thread to the required length, and, 

 while still suspended at the end of its rope, spins the cocoon, 

 which thus becomes fastened to the thread. In a future page 

 will be described a cocoon woven on a similar plan, but made by 

 the caterpillar of one of the moths. 



Mr. Westwood mentions that when examining the cocoon of 

 the Cryptus, he found that it was composed of three distinct lay- 

 ers, that on the exterior being composed of loose silk, which could 

 be wound off like that of the common silkworm, but that the two 

 interior layers were very shining, smooth, and of a gummy mem- 

 braneous texture, thus agreeing with the cocoons of the Burnet 

 Ichneumon. 



Our last example of the pensile nests formed by the hymen- 

 optera is a truly remarkable one. For some time I could scarcely 

 decide upon its place in the present work, whether it was to be 

 ranked as an example of the pensiles, social insects, or builders. 

 On account, however, of the locality which is chosen for it, and 

 the peculiar method by which it is attached to the branch, I have 

 decided upon placing it among the pensile nests. 



It has already been mentioned that the members of the genus 

 Polistes are in the habit of building their cells in the open air, 

 and leaving them without covering to defend them. 



The shape, material, and arrangement of the comb is extremely 

 variable ; some, as that which has already been mentioned, hang- 

 ing their cell-masses to the branches, just as if a number of bee- 

 combs were simply hitched on the twig by the simple process of 

 boring a hole in the upper part of the comb, and pushing the twig 

 through it; others, again, making their cells of mud, in a nearly 

 globular shape, and fastening them on the branches like so many 

 berries. The species, however, which make the cells represented 



