522 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 antennae resume their power of extension, and even the faculty 

 of spirting out their defensive fluid is re-acquired by many beetles. 1 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 (Trichocera hiemalis), which frisked under every bush; 

 to numerous Psychodce ; 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. Of 

 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 antennae 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. 2 



1 Schmid in Illig. Mag. i. 222. 



2 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 Trichocera 

 hiemalis, Psychodce, and numerous other Diptera^ and the bushes were hung with the 

 lines of the gossamer-spider as in 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 

 I found many in a very lively state. Five or six individuals of Haltica Nemorum 



