86 tfATUK^L HISTOET OF 



mals.* On many, taking her rule and compasses"? 

 she draws with precision mathematical figures; 

 points, lines, angles, triangles,f squares, and circles.** 

 Some extensive groups are characterized by the pre- 

 valence of certain hues, bestowed on them probably 

 as a means of concealment from enemies, by assi- 

 milating them to the objects by which they are us- 

 ually surrounded, or in subserviency to some par- 

 ticular purpose in their economy. The prevailing 

 colour among beetles of obscure haunts — such as 

 burrow in the earth, or pass the greater part of their 

 lives under stones (the Geodephagi of some modern 

 systematic writers), as well as those destined to fa- 

 cilitate the decomposition and dispersion of putres- 

 cent and excrementitious substances — is black or 

 brown. The water-beetles (Dytiscidce) are almost 

 uniformly brownish black, inclining to olive, and 

 frequently variegated with streaks and spots of dull 

 yellow. The rostrated beetles, or weevils ( Curcu- 

 liojiidce), present some of the most highly adorned 

 examples of insect life ; and in them also a curious 

 instance is observable of change in colour accom- 

 panying dissimilarity of habit. Numerous kinds of 

 these insects occur among loose earth and sand, or 

 under stones, and these are almost invariably of 

 sombre hues, and destitute of ornament : an exten- 

 sive division of the same tribe inhabit trees and 

 shrubs, and they are remarkable for displaying the 



* Ptinus imperialis, Linn. f Trichius delta, Fab. 



