HYBERNATION OF INSECTS. 555 



\vith under stones, bark, 8ic. In every instance the selected dormi- 

 tory is admirably adapted to the constitution, mode of life, and wants of 

 the occupant. Those insects which can bear considerable cold without 

 injury are careless of providing other than a slight covering ; while the 

 more tender species either enter the earth beyond the reach of frosty or 

 prepare for themselves artificial cavities in substances, such as moss and 

 rotten wood, which conduct heat with difficulty, and defend them from 

 an injuriously low temperature. It does not appear that any perfect 

 insect has the faculty of fabricating for itself a winter abode similar to 

 those formed of silk, &c., by some larvae. Schmid, indeed, has men- 

 tioned finding Rhogium mordax and Inquisitor' in such abodes, con- 

 structed, as he thought, of the inner bark of trees ; but these, as Illiger 

 has suggested, were more probably the deserted dwellings of lepidopterous 

 larvae, of which the beetles in question had taken possession.^ Most 

 insects place themselves in their hybernacula in the attitude which they 

 ordinarily assume when at rest ; but others choose a position peculiar to 

 their winter abode. So most of the ground-beetles (^Eutrcclnun) adhere 

 by their claws to the under side of the stone wliich serves for their retreat, 

 their backs being next to the ground ; in which posture, probably, they 

 are most effectually protected from wet. Gyrohypnus sanguinolentus, and 

 other rove-beetles of the same genus, coils itself up like a snake, with the 

 head in the centre. 



The majority of insects pass the winter in perfect solhude. Occasion- 

 ally, however, several individuals of one species, not merely of such 

 insects as Anchomenus prasinus, a beetle, Pyrrhocoris apferus, a bug, he, 

 which usually in summer also live in a sort of society, but of others which 

 are never seen thus to associate, as Haltica oleracea, Carabus intricatus, 

 and several Goccinella, &c., are found crowded together. This is per- 

 haps often more through accident than design, as individuals of the same 

 species are frequently met with singly ; yet that it is not wholly accidental 

 seems proved by tjie fact that such assemblages are generally of the same 

 genus and even species. Sometimes, however, insects of dissimilar genera 

 and even orders are met with together. Schmid once in February found 

 the rare Lomechusa strumosa torpid in an ant-hill, in the midst of a con- 

 glomerated lump of ants, with which it was closely intertwined."^ 



By far the greater proportion of insects pass the winter only in one or 

 other of the several states of egg, pupa, larva, or imago, but are never 

 found to hybernate in inore than one. Some species, however, depart from 

 this rule. Thus Aphis Rosea, Cardui, and probably many others of the 

 genus, hybernate both in the egg and perfect state^ ; Cynthia Cardui, 

 Gonepteryx Rhamni, and some other species, usually in the pupa, but 

 often in the perfect state also ; and Vanessa lo, according to the accu- 

 rate Brahm, in the three states of egg, pupa, and imago."* It is proba- 

 ble that in these instances the -perfect insects are females, which, not 

 having been impregnated, have their term of life prolonged beyond the 

 ordinary period. 



The first cold weather, after insects have entered their winter quarters,, 

 produces effects upon them similar to those which occur in the dormouse, 



» Illig. Mag. i. 216. » Ibid. i. 491. 



3 Kyber in'Germar, Magazin der Entomologie, ii. 2. * Ins. Kal. ii. 1S8. 



