INSECTS. 173 



five of these encampments may be seen within a foot 

 or two of each other. Against winter they weave 

 and erect a stonger habitation of a rounder form, not 

 divided by any partitions, in which they he heaped 

 up one upon another, each being rolled up. About 

 April they separate, and continue solitary till they 

 assume the chrysalis state. 



Two sorts of caterpillars that feed on the nettle, 

 weave a silken shade over the part which they live 

 upon, and some others which feed on the hawthorn 

 do the same. It frequently happens in a dry sum- 

 mer that the hedges, for a considerable extent, may 

 be seen covered with these webs. 



When the caterpillar of the white cabbage butter- 

 fly is about to assume the chrysalis state, it 

 commonly fixes itself against a wall, under some 

 projection, before undergoing its change, it is need- 

 ful that it should fix itself to the wall by a girth of 

 silk round the body, and by a fastening at the tail, 

 but as the ends of these slender threads would not 

 adhere with sufficient tenacity to stone or brick, it 

 previously covers the space of about an inch long 

 and half an inch wide, with a web of silk, to which 

 extensive base its fastening may be securely fixed. 

 This insect disposes its eggs, generally on the under 

 side of cabbage leaves, side by side, so as to resemble 

 a close column of soldiers, in consequence of which 

 arrangement, on hatching, those caterpillars which 

 proceed from the upper end, cannot disturb the 

 adjoining eggs. 



The intensity of cold which the eggs of insects can 

 withstand is astonishing, for it has been found that 

 even after the most severe winter, their eggs have 

 proved equally prolific with those which have been 

 exposed to mild summers. In the year 1709, the 

 thermometer fell to one degree of Farenheit, and the 

 cold was so intense that its effects were fatal on 

 many animals and plants. Insects were, however, 

 ([uite as numerous as usual in the spring. 



