86 INTRODUCTION' TO 



moss, or stones, the eaves of out-houses, and similar 

 places, are industriously sought after, and many bury 

 themselves a considerable depth in the earth. But 

 the selection of a suitable retreat is far from being 

 their only care, at least with a great many ; other 

 precautions are reso'rted to, many of which aiford 

 examples of singular ingenuity and persevering labour. 

 This is particularly the case with the caterpillars of 

 butterflies and moths. The former either suspend 

 their chrysalides horizontally by the tail and a silken 

 band round the middle, or by the tail alone, allowing 

 the body to hang perpendicularly. The manoeuvres 

 by which the caterpillar manages to place the band 

 round its body are extremely curious and interesting, 

 and have, therefore, been particularly described in the 

 volume of this series already mentioned and to which 

 we must again refer. The cocoons of moths have 

 likewise been described in a similar volume de- 

 voted to their history ; and that tribe of insects af- 

 fords the best examples of this species of fabrication. 

 Most of the Hymenoptera likewise form silken 

 cocoons ; a few Coleopterous and Dipterous genera, 

 (Hypera, Donacia, Mycetophila,) and the Neurop- 

 terous groups Hemerobius and Myrmeleon ; the latter 

 differing from nearly all the rest in having the ap- 

 paratus for spinning their threads at the extremity 

 of the abdomen, instead of in the head. Cocoons of 

 silk are often strengthened by the addition of other 

 materials, such as particles of earth, portions of leaves, 

 fragments of wood, &c. ; and occasionally cocoons are 

 formed altogether of these substances held together by 



