HYBERNATION OF INSECTS. 437 
the same material®, and thus pass the cold season in small 
societies of from two to twelve, under a common cover- 
ing formed of leaves. Bonnet mentions a trait of the 
cleanliness of these insects which is almost ludicrous. 
He observed in one of these nests a sort of sack contain- 
ing nothing but grains of excrement; and a friend 
assured him that he had seen one of these caterpillars 
partly protrude itself out of its case, the hind feet first, 
to eject a similar grain ; so that it would seem the society 
haye on their establishment a scavenger, whose business it 
is to sweep the streets and convey the rejectamenta to one 
grand repository>! This, however singular, is rendered 
not improbable from the fact that beavers dig in their ha- 
bitations holes solely destined for a like purpose ‘*. 
A very considerable number of insects hybernate in the 
perfect state, chiefly of the orders Coleoptera, Hemiptera, 
Hymenoptera, and Diptera, and especially of the first. 
Papilio Urtice, Io, and a few other lepidopterous species, 
with a small proportion of the other orders, occasionally 
survive the winter; but the bulk of these are rarely 
found to hybernate as perfect insects. Of coleopterous 
insects, Schmid, to whom we are indebted for some va- 
2 J have reason to think that the larve of some species of Heme- 
robius thus protect themselves by a net-like case of silken threads ; 
at least I found one to-day (December 3d, 1816) inclosed in a case 
of this description concealed under the bark of a tree: and it is not 
very likely that it could be a cocoon, both because the inhabitant 
was not a pupa, which state, according to Reaumur, is assumed soon 
after the cocoon is fabricated (ili. 385); and because the same author 
describes the cocoons of these insects as perfectly spherical and of a 
very close texture (384); while this was oblong, and the net-work 
with rather wide meshes. 
> uv. i. 72. © [bid. ix. 167. 
