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89 
may naturally suggest that of annual torpor, by 
which some of almost every class are affected. The 
most familiar instances present themselves in the 
hybernation of snails, which congregate towards the 
end of autumn; close up the orifice of their shells by 
a horny cuticle, and secrete themselves in cavities of 
trees and walls during the winter months; and in 
the deep burrowing of grubs and slugs, and worms, 
of mole-crickets, &c. 
Hybernation. 
« A much greater number of insects pass the 
winter in the pupa than in the egg state; probably 
nine tenths of the extensive order lepidoptera, many 
of the hymenoptera, and several in other orders.” 
* To the class of insects which hybernate in the 
larva state, belong, in the first place, all those which 
exist under that form more than one year; as many 
melolonthe, elateres, cerambyces,” &c. 
A very considerable number of insects will be 
found to winter in the perfect state: chiefly of the 
orders coleoptera, hemiptera, bymenoptera, and di- 
ptera. Papilio, urticze, io, and a few other lepido- 
ptera, occasionally survive the winter ™.” 
They seek different situations. Some crowd toge- 
ther in torpid society ; some, like hermits, torpify in 
solitude. The aquatic tribes, dytisci, burrow into 
the mud of their pools. “ In every instance,” says 
Kirby, “the selected dormitory is admirably adapted 
™ Kirby, vol. ii. p. 435, &c. 
