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no energy expended in movement, and respiration and all other 

 vital functions are reduced to a minimum. This phenomenon of 

 hibernation is, as already indicated, very much more complete in 

 some insects than in others ; it may indeed be considered as an 

 attempt to reassume, temporarily, the resting stage of the egg or 

 pupa. The very attitude taken up by a hibernating wasp for 

 instance, with the legs folded ventrally, the tarsi directed backwards, 

 and the wings also folded ventrally, between the second and third 

 pair of legs, recalls exactly that of the pupa ; the insects only grip 

 being by means of the jaws firmly closed and grasping some stem 

 or fibre. This attitude is quite different from the ordinary resting 

 attitude of the wasp, when the wings aie folded down the back, and 

 the grip maintained by the feet, and is never assumed except for 

 purposes of hibernation. 



In this case the insect is said to hibernate, by which term is 

 meant to enter into a torpid condition, during which no food is 

 taken, no energy expended in movement, so that respiration and all 

 other vital functions are reduced to a minimum. This phenomenon 

 of hibernation is, as already indicated, very much more complete 

 in some insects than in others ; it may, indeed, be considered as an 

 attempt to reassume temporarily the resting state of the egg or 

 pupa. The very attitude taken up by a hibernating wasp, for 

 instance, with the legs folded ventrally, the tarsi directed back- 

 wards, and the wings also folded ventrally between the second and 

 third pair of legs, recalls exactly that of the pupa, the insect's only 

 grip being by means of the jaws firmly closed and grasping some 

 stem or fibre. This attitude is quite dift'erent from the ordinary 

 resting attitude of the wasp, when the wings are folded down the 

 back, and the grip maintained by the feet, and is never assumed 

 except for purposes of hibernation. 



What are the precise factors that bring about hibernation has 

 puzzled many investigators. That it is not cold alone is evident 

 from the fact that many hibernating insects take up their winter 

 quarters long before cold weather sets in. Also, exposure to cold 

 artificially produced does not necessarily induce hibernation. 

 Similarly, it is not lack of food that induces hibernation, since 

 many insects, both larvae and adults, commence hibernating many 

 weeks before there is any scarcity of food. Nevertheless, it appears 

 that the absence of food at the end of the period may conduce to 

 a considerable prolongation of the hibernating state. Dr. Chapman 

 records observations on the larvae of Leioptiltis tephradactijla (6). The 



