HYBERNATION OF INSECTS. 523 
All insects, however, do not undergo this degree of torpidity. In fact, 
there are some, though but few, which cannot, at least in our climate, 
strictly be said to hybernate, understanding by that term passing the winter 
in one selected situation in a greater or less degree of torpor, without food. 
Not to mention Cheimatobia brumata, and some other moths, which are 
disclosed from the pup in the middle of winter, and can therefore be 
scarcely regarded as exceptions to the rule, some insects are torpid only in 
very severe weather, and on fine mild days in winter come out to eat. This 
is the case with the larva of Buprepia fuliginosa* ; and Lyonet asserts that 
there are many other caterpillars which eat and grow even in the midst of 
slight frost.2 Amongst perfect insects, troops of Z'richocera hiemalis, the 
gnat whose choral dances have been before described, may be constantly 
seen gambolling in the air in the depth of winter, when it is mild and calm, 
accompanied by the little Psychoda, so common in windows, several Zus- 
cide, spiders, and occasionally some Aphodii and Staphylinide: and the 
societies of ants, as well as their attendant Aphides, are in motion and take 
more or less food during the whole of that season, when the cold is not 
intense. The younger Huber informs us that ants become torpid only at 
2° Reaum. below freezing (27° Fahrenheit), and apparently endeavour to 
preserve themselves from the cold, when its approach is gradual, by clus- 
tering together. When the temperature is above this point they follow 
their ordinary habits (he has seen them even walk upon the snow), and can 
then obtain the little food which they require in winter from their cows, 
the Aphides, which, by an admirable provision, become lethargic at precisely 
the same degree of cold as the ants, and awake at the same period with 
them. Humboldt also found insects upon the Cordilleras, above the limits 
of snow, which, although not natives of this altitude, retained their vivacity 
at this low temperature.* 
Lastly, there are some few insects which do not seem ever to be torpid, 
as Podura nivalis L., Boreus hiemalis Latr., and the singular apterous insect, 
first described by Dalman, Chionea araneides®, all of which run*with agility 
on the snow itself; and which last, both from its spider-like form and sin- 
gular habitat, must, as Macquart has well observed ®, have caused its fortu- 
nate discoverer as.much astonishment as that felt by the botanist who first 
found the red-coloured Protococcus nivalis (whatever may be decided as to 
its being a plant or an animalcule) in a similar situation ; or, as may be 
added, that of M. Lefebvre on first observing the Mantis (Hremiophila), 
were still very lethargic; and two of Geotrupes stercorarius, which I accidentally dug 
up from their hybernacula in the earth, at the depth of six or eight inches, though 
the Acari upon them were quite alert, exhibited every symptom of complete torpor. 
1 Brahm, Jns. Kal. ii. 31. 2 Lesser, |. i. 255. 
5 Recherches, 202. In digging in my garden on the 26th of January, 1817, I 
turned up in three or four places colonies of Myrmica rubra Latr. in their winter re~ 
treats, each of which comprised apparently one or two hundred ants, with several 
larve as big as a grain of mustard, closely clustered together, occupying a cavity 
the size of a hen’s egg, in tenacious clay, at the depth of six inches from the surface. 
They were very lively; but though Iahrenheit’s thermometer stood at 47° in the 
shade, I did not then, nor at any other time during the very mild winter, see a single 
ant out of its hybernaculum. 
4 Burmeister, Manual of Ent. 508. 
5 Kongl. Vet. Acad. Handling. 1816, 104. 6 Dipteres, i. 74, 
