374 



HYBERNATION OF INSECTS. 



we have often days in winter milder than at the period of hy- 

 bernating, and in which insects are so roused from their tor- 

 pidity as to run about nimbly when molested in their retreats ; 

 yet, though their irritability must have been increased by a 

 .two or three months' inactivity and abstinence, they do not 

 leave them, but quietly remain until a fresh accession of cold 

 again induces insensibility. 



In short, to refer the hybernation of insects to the mere 

 direct influence of cold is to suppose one of the most impor- 

 tant acts of their existence given up to the blind guidance of 

 feelings which in the variable climates of Europe would be 

 leading them into perpetual and fatal errors — which in spring 

 would be inducing them to quit their ordinary occupations, 

 and prepare retreats and habitations for winter to be quitted 

 again as soon as a few fine days had dispelled the frosty feel of 

 a May week ; and in a mild winter's day, when the thermo- 

 meter, as is often the case, rises to 50° or 55°, would lure them 

 to an exposure that must destroy them. It is not, we may 

 rest assured, to such a deceptious guide that the Creator has 

 intrusted the safety of so important a part of his creatures : 

 their destinies are regulated by feelings far less liable to err. 



What, you will ask, is this regulator? I answer, Instinct — 

 that faculty to which so many other of the equally surprising 

 actions of insects are to be referred; and which alone can 

 adequately account for the phenomena to be explained. 

 Why, indeed, should we think it necessary to go further? 

 We are content to refer to instinct the retirement of insects 

 into the earth previously to becoming pupae, and the cocoons 

 which they then fabricate ; and why should we not attribute 

 to the same energy their retreat into appropriate hybernacula, 

 and the construction by many species of habitations expressly 

 destined for their winter- residence ? The cases are exactly 

 analogous ; and the insect knows no more that its hy- 

 bernaculum is to protect it from too severe a degree of cold 

 during winter than does the full-fed caterpillar when it 

 enters the earth that it shall emerge a beauteous moth. 1 



I am, &c. 



1 The reasoning in the preceding pages, as to cold not being the sole and 

 direct cause of hybernation in insects, is strongly confirmed by the facts 



