350 



HYBERNATION OF INSECTS. 



reach of frost ; and Avith the latter, Clisiocampa neustria, La- 

 siocampa castrensis, Hypogymna dispar, and some other moths, 

 departing from the ordinary instinct of their congeners, which 

 teaches them to place their eggs upon the leaves of plants, fix 

 theirs to the stem and branches only. That this variation of 

 procedure has reference to the hybernation of the eggs of 

 these particular species, is abundantly obvious. Insects whose 

 eggs are to be hatched in summer usually fix them slightly 

 to the leaves upon which the larvae are to feed. But it is 

 evident that, were this plan to be adopted by those whose 

 eggs remain through the winter, their progeny might be blown 

 away along with the leaf to which they are attached, far from 

 their destined food. These, therefore, choose a more stable 

 support, and carefully fasten them, as has just been observed, 

 either to the trunk or branches of the tree, whose young 

 leaves in spring are to be the food of the excluded larvae. 

 The latter plan is followed by the female of Clisiocampa neu- 

 stria, which curiously gums her eggs in bracelets round the 

 twigs of the hawthorn, &c. But another provision is de- 

 manded. Were these eggs of the usual delicate consistence, 

 and to be attached with the ordinary slight gluten, they would 

 have a poor chance of surviving the storms of rain and snow 

 and hail to which for six or eight months they are exposed. 

 They are therefore covered with a shell much more hard and 

 thick than common; packed as closely as possible to each 

 other ; and the interstices are filled up with a tenacious gum, 

 which soon hardens the whole into a solid mass almost capable 

 of resisting a penknife. Thus secured, they defy the elements, 

 and brave the blasts of winter uninjured. The female of 

 Hypogymna dispar, whose eggs have a more tender shell, glues 

 them in an oval mass to the stem of a tree (whence the Ger- 

 man gardeners call the larvae Stamm-raupe), and then covers 

 them with a warm non-conducting coat of hairs plucked from 

 her own body, equally impervious to cold and wet. 



Another of those beautiful relations between objects at 

 first sight apparently unconnected, which at every step reward 

 the votaries of entomology, is afforded by the coincidence 

 between the period of the hatching in spring of eggs deposited 

 before winter, and of the leafing of the trees upon which they 



