INSECTS. 77 



also gradually becomes covered with a firm and shell-like coat or 

 case. This is a thickening and induration of the skin of the grub, 

 not of the epidermis or cuticle ; for that is gradually cast as a slough, 

 in proportion as the work of transformation proceeds. The chry- 

 salis is soon formed ; some insects envelop themselves in a web, as 

 the silkworm, <fcc. ; others do not. During this stage, the insect is, 

 of course, perfectly harmless. In course of time, the perfect insect 

 is formed within its shelly sheath ; it now commences the work of 

 breaking open its prison, having effected which, it emerges in all 

 the beauty of insect perfection. 



CATERPILLARS do not prey indiscriminately on all sorts of herb- 

 age or farming produce. Each species has its favorite plant, or 

 plants ; and not even starvation will induce it to transgress these 

 limits that instinct has assigned to its appetite, or eat of a plant of 

 another sort. 



THE WIREWORM, AND PARENT BEETLES, MALE AND FEMALE. 



One of the most destructive grubs which infests the fields of the 

 agriculturist, or renders futile the care and skill of the gardener, is, 

 perhaps, that well-known larva the WIREWORM. I may here ob- 

 serve that the general name of wireworm is given to the larva of 

 many species of beetle, all, however, very similar in habits and ap- 

 pearance, and so equally gifted as to their destructive powers, that 

 it would be difficult, indeed, to draw any distinction in this respect 

 between them. 



Scarcely any land is free from the ravtges of some one or other 

 of the wireworms ; and there is scarcely any description of crop 

 upon which they will not prey with equal greediness. Wherever 

 grass or any sort of herbage will grow, there will the greedy 

 wireworm le found. The beetles, of which the wireworms are 

 the larvae, <-:e those called the ELATERS ; also spring-beetles, skip- 



