REST UF INSECTS. 407 



of flies let loose, while many still remained ' infixed 

 and frozen round.' A still stronger instance is men- 

 tioned by Ellis, in which a large black mass, like 

 coal or peat upon the hearth, dissolved, when thrown 

 upon the tire, into a cloud of mosquitoes {Culicidce.)* 

 It has been remarked by most writers upon the 

 torpidity of warm-blooded animals, that cold does 

 not seem to be its only cause, and the same appa- 

 rently holds in the case of insects. Bees, ir.deed, 

 which remain semi-torpid during the winter, may be 

 prematurely animated into activity by the occurrence 

 of some days of extraordinary mildness in spring ; 

 but, what is not a little wonderful and inexplicable, 

 they are not roused by much milder weather when 

 it occurs before Christmas, — on the same principle, 

 perhaps, that a man is more easily awakened after he 

 has slept six or seven hours than in the earlier part 

 of the night. Immediately after the first severe frost 

 in the winter of 18i29-.30, we dug down into the 

 lower chambers of a nest of the wood-ant (Formica 

 rufa), at Forest Hill, Kent, which we had thatched 

 thickly with fern-leaves the preceding November, both 

 to mark the spot and to protect the ants in winter. 

 About two feet deep we found the little colonists all 

 huddled up in contiguous separate chambers, quite 

 motionless till they were exposed to the warm sun- 

 shine, when they began to drag themselves slug- 

 gishly and reluctantly along. Even upon bringing 

 some of them into a warm room, they did not awaken 

 into summer activity, but remained lethargic, un- 

 willing to move, and refusing to eat, and continued 

 in the same state of semi- torpidity till their brethren 

 in the woods began to bestir themselves to repair the 

 damages caused by the winter storms in the out- 

 works of their encampments, f 



* Quarterly Review, April 1821, p. 200. t J. R. 



