234 NATURAL ARRANGEMENT OP INSECTS. 



(207.) The Trogince are the next great division among 

 the terrestrial scarabs. They have been compared by 

 Mr. MacLeay, and very justly, to the genus Hister: 

 both appear to be fond of cadaverous matter; both " have 

 their head sunk in the thorax in a very peculiar man- 

 ner; and both have the curious habit, when alarmed, of 

 counterfeiting death, by applying their feet and antennae 

 close to the body, and ceasing all motion until their fear 

 may have subsided." We may add to these analogies, 

 the Linnaean genera Ptinus, Dermestes, Cassida, Cur- 

 culiOy Elater, Buprestis, and several others ; all of which, 

 in their own proper circles, are types of the MONILICOR- 

 NES. They are also related to the Melolonthin^., not 

 only by their very convex body and obtuse head, but by 

 the very same habit of counterfeiting death, which the 

 Melolonthina possess in a very high degree.* Here, 

 however, the similarity ceases. The Trogina, in compa- 

 rison to the other divisions, are remarkably few, and 

 but very little diversified either in colour or in form : 

 they are all small insects ; and possess the peculiarity, 

 almost unknown in others of this family, of having the 

 elytra deeply and thickly marked by excavated hollows. 

 Some of them are apterous, another point of analogy 

 they bear to several of the monilicorn types; while one 

 (Trox luridus Fab.) is said to have been found in rotten 

 wood.f The external resemblance between these insects 

 and some of the small Melolonthince^ such as Serica, &c., 

 is well worthy of attention. The Trogidce, at first sight, 

 seem to be a much more isolated group among the sa- 

 prophagous Petalocera, than what we suspect they really 

 are. Among the smaller types, or sub-genera, of the 

 Dynastince, there are several insects which appear to 

 form a very gradual passage between the two, although 

 we have not yet been able to discover the point of junc- 

 tion : this, however, will not in the least militate 



* The common cockchafer will continue this deception even if thrown up 

 in the air; instead of spreading its wings, it will fall to the ground as if it 

 were really dead. 



f Hor. Ent., p. 63. 



