THE PREDATORES. 249 



the true water insects, and which circumstance seems 

 to remove it from that group, besides its other pecu- 

 liarities, swims by moving the posterior legs alternately, 

 and not simultaneously. We find in this group, again, a 

 slight metallic tinge in the colouring, as in many species 

 of Berosus, and in the thorax of Elophorus. Their ha- 

 bits are exceedingly obscure ; nothing is known of them 

 beyond their habitat, although they are found exten- 

 sively in this country. Sphceridium evinces its rela- 

 tionship to this group, by the under side of the body 

 resembling the JSlophori, and its antennae, anterior tarsi, 

 and palpi approaching it to Hydropliilus; whilst its 

 habit of frequenting dung, and its circular form, give 

 it a strong resemblance to Geotrupes, in the circle 

 of the Scarabceida. The group likewise embraces 

 a multitude of small genera, such as Spercheus, Ochthe- 

 bius, Hydrena, &c., the habits of which are, evidently, 

 greatly uniform ; and we may further observe, that the 

 intertropical species of all these genera are, apparently, 

 always less than their more northern congeners, and in 

 some, especially the aquatic genera, they are very nu- 

 merous.. It is not improbable that Heterocerus, Par- 

 nus and Elmis may be aberrant constituents of this 

 group. [W. E> Sh.] 



CHAP. VIL 



COLEOPTERA, continued. 



PREDATORES. 



(223.) THE most rapacious of all beetles are com- 

 prised in the tribe of Predatores, which, in the fore- 

 going arrangement, we place as the sub- typical, or car- 

 nivorous, group of the Coleoptera, a rank and station 

 which is established by the analogy subsisting between 



