THE PREDATORES. 



251 



they still resemble the typical forms ; and although they 

 inhabit a different element, they are equally rapacious. — 

 subsisting only upon smaller water insects. This family, 

 composing the aquatic division of the tribe, constitutes 

 the true point of junction between the predacious and 

 the lamellicorn beetles, — an affinity which entirely con- 

 tradicts the supposition that the Hydrodephagce MacL. 

 is one of the " normal," or, more properly, typical 

 groups. The very few genera of the Dytiscidce here 

 occasions an interruption in the series, which leaves 

 much uncertainty as to the precise point of junction 

 between them and the Silphidce : nevertheless, as some 

 authors insist upon an affinity between these latter in- 

 sects, and such genera as Leiodes, Agathidium, Catops, 

 and Choleva *, we have no great hesitation in adopting 

 their views, and placing the Necroplmga Latr. as part of 

 the most aberrant family of the present tribe, under the 

 more appropriate name of Silphidce. Judging from 

 analogy, however, we have an impression that Pimelia 

 is the true type of this family : its analogy to the 

 Chrysomelidce, in its thick and globose body, is quite 

 obvious ; while its affinity, on one side to Blaps, and 

 on the other to Silpha, are further inducements to our 

 belief that this is their true station. All these insects, 

 in fact, are in some degree carnivorous, although their 

 animal food is only derived from dead or decomposed 

 substances ; they are the only Predatores which, in ai.*y 

 degree, derive nourishment from vegetable substances. 

 How far the Engidce MacL., and such genera as Ero- 

 tylus\ really enter into this assemblage, or are merely 



* Latreille considered the Parniilce so allied to Gyrinus, that he once 

 included them in the same family ; and, as both are more or less 

 aquatic, they would seem to oft'er, with the above, additional links in 

 the chain. 



f " It is perhaps by the Erotyli that the opposite points of the circle of 

 Culeoptera meet." — Ann. Jav. \^. W. And again, the same author ob- 

 serves, " As to the Eroti/libe'nig tetramerous, it is a circumstance to which 

 little importance ought to be attached, since the five articulations of the 

 tarsi are visible in several species ; and other insects, which are close to 

 the genus, such as Mr. Kirby's Spheniscus, are heteromerous. 



