274 HOMES WITHOUT HANDS. 



fastened firmly together, so as to form a flattish mass extremely 

 variable in shape and size, the latter depending on the number 

 of cocoons. One of these masses now before me consists of one 

 hundred and seventeen cocoons, and its shape is that of a 

 segment of a circle, fixed to the twig by the flat side. 



The ends of the cocoons are both closed, but when the young 

 Ichneumon is hatched it makes its exit by cutting a circular flap 

 from one end of the cocoon, pushing the flap outwards and then 

 creeping into the air. The insects are quite indifferent as to the 

 end of the cocoon through which they escape, and in the example 

 before me nearly two-thirds of the creatures have escaped out of 

 one end and the remaining third out of the other. 



The texture of these cocoons is very firm and stiff, and the 

 silken material is so closely fitted together as to be completely 

 waterproof. The microscope shows that the exterior of the cocoon 

 is composed of white sUken fibres matted tightly together, and 

 rather rough, while the inside of the circular flap shows that the 

 interior of each cocoon is smooth, hard, and of a pale yellow hue. 



The longest and largest cells occupy the centre of the mass, 

 while those at either end are shorter, smaller, and fewer, being 

 about one-fifth of the entire number. Knowing the customs of 

 most hymenopterous insects, we may conclude that the females 

 occupy the centre and the males the extremities. 



Theee is a very remarkable pensile cocoon constructed by the 

 larva of another hymenopterous insect belonging to the same 

 family as the Burnet ichneumon, and placed in the genus Cryptus. 



The insects of this genus seem to construct a strange variety 

 of cocoons, some being white, some yellow, and some banded and 

 mottled with black. The most remarkable forms, however, are 

 those in which the cocoon is attached to a thread some inches in 

 length, the other end of which is fastened to a bough or a leaf 

 Edaumur, 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 enclosed insect was able to bend itself and then suddenly 

 straighten the body. 



K4aumur believes that the Ichneumons which make these 

 pensile cocoons are parasitic on the processionary caterpillars, 

 because he found them plentiful near the nests of these insects. 



