814 Thk Zoologist — August, 1866. 



settlement of an insect which becomes, as it were, so intoxicated with 

 dt'ligbt that it is kept stationary while providential Nature puts her 

 melting process into operation, it seems to me, when looking at the 

 general question of these de]>ressions, that we must exempt species 

 which are absolutely peculiar to the heights, from even a share in (at 

 all events) the commencement of the phenomena ; for it is hardly 

 likely that ihei/ would become seriously affected by conditions of 

 temperature which must take place annually within their appointed 

 range, and which their life-histories would doubtless show us to be the 

 rule rather than the exception. But the case is far otherwise with 

 the denizens of a warmer zone; for if they perchance should find 

 themselves, by the force of circumstances, in an atmosphere more 

 frozen and rarificd than that for which they were destined, the results 

 which Mr. Miiller has so graphically described, and which are apt to 

 be experienced by ourselves when overtaken in the regions of perpetual 

 snow, might be considered not only as possible, but as even a priori 

 probable. And I should therefore argue, that the species thus acted 

 upon, and ultimately destroyed, would not be the slriclbj "alpine" 

 ones, but more often those which had been brought up from the lower 

 districts. 



The above conclusion would at least, I think, hold good in 

 accounting for, at any rate the beginnings of cavities such as those 

 which I myself met with ; as well as for the entire elaboration of the 

 small and cylindrical ones, observed by Mr. Pascoe, in which a single 

 insect only appears to have been concerned. But it is not difficult to 

 conceive that, where a nucleus has been established by a solitary indi- 

 vidual (one probably from a more genial temperature), the hole thus 

 commenced might sometimes prove a trap for even peculiarly alpine 

 forms — which, in their turn, would contribute their quantum of united 

 warmth, which they had previously absorbed from the direct rays of 

 an unclouded sun, to increase the dimensions of the hollow. It would 

 be by some such explanation as this that I should account for the fact 

 that the Coleoptera which I took at the head of the St. Gothard Pass, 

 wilhin the little basins which had been shaped out in the snow, were 

 for the most part such as are exclusirely alpine in their habits. And, 

 hence (I may add) follows the desirability of ascertaining for certain, 

 in all instances, what the species actually are, for it is by that means 

 alone that we can arrive at a true solution of the present problem ; 

 and that, consequently, any traveller who may have the opportunity 

 of chronicling the phenomena which Mr, MUller has specified 



