72 THE SNOW-FLEA DESCRIBED. 



of the Alpine rose (rhododendron f err ngineum and rhododendron 

 hirsufum.) 



The coleoptera have also numerous representatives in the 

 region of perpetual snows, with this difference equally charac- 

 teristic of other animals that, upon the southern declivity, 

 they ascend 1000 to 1500 feet higher than on the northern. 

 We may mention, as specially distributed in the topmost zone 

 of the Alpine world : 



The Chrysomela salicina, a pretty little beetle, sometimes 

 blue, sometimes deep green, and finely punctuated, which lives 

 almost exclusively upon a species of dwarf willow (Salix 

 retusd). 



The Nebria Escheri, a black beetle, about two thirds 

 of an inch long, with feet and antennae of a brownish 

 red; and 



The Nebria Chevrierii, with rust-coloured feet and antennae, 

 common in the sources of the Rhine. 



Special mention must be made of the Snow-Flea. Do not 

 think we are referring to an insect of the same species as our 

 common fleas : the snow-flea approximates much more closely 

 to the lice family than to the fleas, though it hops like the 

 latter. The history of its discovery dates back as far as 1839. 

 At this epoch, M. Desor, a learned Swiss naturalist, had 

 undertaken some researches upon the glaciers. Accompanied 

 by some friends, he set out from the hospice of the Grimsel, 

 and arrived in the vicinity of the glacier of the Lower Aar, 



