622 HYBERNATION OF INSECTS. 
external symptoms of death. In this state it continues during the existence 
of great cold, but the degree of its torpidity varies with the temperature of the 
atmosphere. The recurrence of a mild day, such as we sometimes have in 
winter, infuses a partial animation into the stiffened animal: if disturbed, 
its limbs and antenne resume their power of extension, and even the faculty 
of spirting out their defensive fluid is re-acquired by many beetles.! But 
however mild the atmosphere in winter, the great bulk of hybernating in- 
sects, as if conscious of the deceptious nature of their pleasurable feelings, 
and that no food could then be procured, never quit their quarters, but 
quietly wait for a renewal of their insensibility by a fresh accession of 
cold, 
On this head I have had an opportunity of making some observations 
which, in the paucity of recorded facts on the hybernation of insects, you 
may not be sorry to have laid before you. The 2nd of December, 1816, was 
even finer than many of the preceding days of the season, which so happily 
falsified the predictions that the unprecedented dismal summer would be 
followed by a severe winter. ‘The thermometer was 46° in the shade; not 
a breath of air was stirring; and a bright sun imparted animation to troops 
of the winter gnat (Zvichocera hiemalis), which frisked under every bush; 
to numerons Psychode ; and even to the flesh-fly, of which two or three 
individuals buzzed past me while digging in my garden. Yet though these 
insects, which I shall shortly advert to as exceptions to the general rule, 
were thus active, the heat was not sufficient to induce their hybernating 
brethren to quit their retreats. Removing some of the dead bark of an old 
apple-tree, I soon discovered several insects in their winter quarters. Ot 
the little beetle Dromius quadrinotatus, I found six or eight individuals, and 
all so lively, that, though remaining perfectly quiet in their abode until dis- 
turbed, they ran about with their ordinary activity as soon as the covering 
of bark was displaced. The same was the case with a colony of earwigs. 
Two or three individuals of Dromius quadrimaculatus showed more tor- 
pidity. When first uncovered, their antennz were laid back; and it was 
only after the sun had shone some seconds upon them that they exhibited 
symptoms of animation, and, after stretching out these organs, began to 
walk. Close by them lay a single weevil (Anthonomus Pomorum), but in so 
deep a sleep that at first I thought it dead. It gave no sign of life when 
placed on my hand, quite hot with the exercise of digging ; and it was only 
after being kept there some seconds, and breathed upon several times, that 
it first slowly unfolded its rostrum, and then its limbs, It deserves remark, 
that all these insects, thus differently affected, were on the same side of the 
tree, under a similar covering of bark, and apparently equally exposed to 
the sun, which shone full upon the covering of their retreat.? 
1 Schmid in Illig. Mag. i. 222. 
® Since writing the above, I have had another opportunity of confirming the ob- 
servations here made, ‘The last week of January, 1817 in the neighbourhood of 
Hull, was most delicious weather — calm, sunny, dry, and genial — the wind south- 
west, the thermometer from 47° to 52° every day, and at night rarely below 40°; in 
fact, a week much finer than we can often boast of in May: the 27th of the month 
was the most delightful day of the whole: the air swarmed with 'richocera 
hiemalis, Psychode, and numerous other Diptera, and the bushes were hung with the 
lines of the gossamer-spider asin autumn. Yet with the exception of Aphodius con- 
taminatus, I did not observe a single coleopterous insect on the wing, nor even an 
individual tempted to crawl on the trunks of the trees, under the dead bark of which 
TYound many in a very lively state, Five or six individuals of Haltica Nemorum 
