218 PTILOTA. 



with the adjacent materials. Some few larvae, however, as 

 those of the ant-lion {Myrmeleon), and the lace-winged 

 aphidivorous flies (Hemerobius), have the spinning apparatus 

 placed at the extremity of the body. 



Some cocoons are formed simply of a few threads, spun 

 into an open-work case, which permits the inclosed insect 

 to be plainly perceived through the meshes ; this is the case 

 with the gipsy and satin moths {Hypogymna dispar and 

 Leucoma salicis), &c. Such is also the case with the cocoons 

 of some of the weevils and chrysomelideous beetles. The 

 cream-spotted tiger-moth {Arctia villica) is more careful, 

 forming a much closer cocoon, but which, nevertheless, per- 

 mits the inclosed chrj^salis to be seen through the small 

 meshes. This cocoon is moreover defended, by being formed 

 in the middle of a bunch of leaves ; and here it is interest- 

 ing to notice, that those caterpillars which are furnished 

 with a short supply of silk, are nevertheless very anxious to 

 conceal their slight cocoon in the most effectual manner, by 

 attaching together with silken cords the adjacent leaves ; 

 sometimes two or three being drawn together, so as to meet 

 at the edges, and sometimes a single leaf being pulled out of 

 its natural position, so as to form a complete covering to 

 the cocoon. Sometimes, moreover, several caterpillars unite 

 together, so as by their combined strength to secure several 

 leaves more firmly together, within which they then, in com- 

 pany, undergo their transformations. Even many caterpillars, 

 which spin a very compact cocoon, resort to the same kind 

 of manoeuvre, rather, I should presume, as a means of sup- 

 port than of defence. Other curious means are adopted by 

 some larvae, for the i)urpose of rendering their slightly formed 

 cocoons more opaque ; thus by some a kind of paste-like 

 matter is secreted from the anus, which, being apphed by 

 the head upon the entire inner surface of the cocoon, 

 hardens and forms a powder, which completely answers the 



