86 KATUEAL HISTORY OF 



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

 she draws with precision mathematical figures 5 

 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- 

 cerit 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- 

 lionidce), 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 

 snrubs, and they are remarkable for displaying the 



* Ptinus imperialis^ Linn. f Trichius delta t Fab. 



