54 THE entomologist's record. 



of multiplication, and in others a protective adaptation) may have 

 constituted a " resting habit," transmitted with suitable modifications 

 to higher forms of life. In his statement of the case I venture to take 

 exception to the preliminary proposition that just as protoplasm pos- 

 sesses the quality of giving rise to vital manifestations, " so all (or 

 nearly all) living matter posseses the capacity of assuming a resting 

 state." Have we sufficient warrant for such an assertion ? No doubt 

 the germs of vegetable organisms, and in many cases the ova or sper- 

 matozoa of certain worms, parasitic Crustacea, and some insects, do 

 retain their vitality unimpared for surprising lengths of time under 

 certain conditions, or in suitable receptacles. And it is also true that 

 many insects and animals in either the immature or perfect stages can 

 remain torpid under certain circumstances, and thus survive accidents 

 of environment otherwise fatal ; but the statement excepted to is so 

 wide that it appears an argument from the particular to the general. 

 But the contention is unimportant, as even if the habit were very rare 

 and only occasional, nevertheless we may grant that it may have been 

 transmitted to the Lepidoptera in some shape or form. It would have 

 been more pertinent, however, in supporting the contention, if parallel 

 resting habits had been instanced in the Orthoptera and Neuroptera, 

 closely allied forms of which have been foiuid in rocks of a far earlier 

 formation than any containing fossil Lepidoptera ; and if the deriva- 

 tion of this protective adaptation had been sought among those aquatic 

 insects from whose stock many zoologists hold the Order Lepidoptera 

 to have taken rise. 



I am unwilling, however (to say nothing of incompetency), to follow 

 the ingenious writer on such a speculative excursus. I prefer to try 

 whether less remote causes can be adduced in explanation. To the 

 question whether a causal connexion between cold and hybernation 

 can be proved, I think I may fairly take my stand, firstly upon the 

 acknowledged fact that the habit seems to be confined to those species 

 of Lepidoptera now inhabiting regions subjected to winter conditions ; 

 for if it were a very primitive trait, we should expect to find analogous 

 phenomena surviving among tropical insects. Mr. Tutt suggests that 

 there may be such, but brings forward no example. And, further, it is 

 undeniable that cold as well as excessive heat directly induces torpidity 

 among both higher and lower animals. Humboldt, Waterton and 

 other authors, refer to the stillness of tropical forests during the 

 hottest hours of the day — animated nature taking a siesta. And who 

 has not noticed the sudden failure of energy among butterflies and 

 day-flying moths when a cloud obscures the sun ? On the Alps, 

 butterflies are so paralysed by the sudden failure of heat vibrations 

 that they settle at once, and often can be taken by the hand. Unless 

 they pitch on snow patches, as is occasionally the case, which proves 

 fatal, they remain in a torpid state for considerable periods, until sun- 

 shine again revives them. Here, at any rate, we have an immediate 

 result from the lowering of temperature. Capacity for resisting cold 

 is, as the writer says, exhibited in varying degrees by the Lepidoptera 

 in various stages, and natural selection has fitted some rather than 

 others to siuwive the winter. The ingenious theory propounded seems 

 therefore put forward through the necessity of explaining only a com- 

 paratively small number of peculiar cases. The instances given are 

 undoubtedly most cui-ious and puzzling, but I do not see that they are 

 inexplicable from the standpoint of natural selection. The writer 



