COLEOPTEBA. 



HETEROMERA. 



ALTHOUGH a large number of genera and several thousand species have 

 been described as belonging to this group, yet we know comparatively 

 little regarding it; it is the most anomalous and in many respects the 

 least satisfactory of all the divisions of the Coleoptera ; the chief character 

 by which its members are distinguished, and from which it takes its 

 name, is the fact that the anterior and intermediate tarsi are 5-jointed 

 and the posterior tarsi 4-jointed ; there are, however, many heterome- 

 rous beetles in the other large series, as, for instance, Anisotonvi, Acritus, 

 the male of Rhizophagus, &c., so that the character by no means holds 

 rood in all cases, and there is no other upon which it can be strictly de- 

 Kned ; and yet it must be allowed after all that the Heteromera as a 

 whole are easily separated from the other groups, and that very few 

 foreign elements have ever been introduced amongst them ; in general 

 form they differ in an extraordinary degree, and seem to present affinities 

 towards 'almost all the other groups ; even in our very limited number 

 of genera and species this is very obvious ; thus Rhinotimus resembles 

 certain Curculionidae, while Diaperis and Phitydtma might be taken for 

 Chrysomelidte, and (E<lem> -ret, Xacerdes, Lytta, and Pyrocliroa for Ma- 

 lacodermata; Tribolium again appears to be allied to the Cryptophagidae, 

 Hypoplilceus to the Colydiidse, and certain species of Ci stela to the 

 Longicornia ; other species again are entirely anomalous both in their 

 appearance and their life history ; among these may be mentioned Meloe 

 Sitaris, and Metaecus. 



The following are the chief characters of the division as given by 

 Thomson : Anterior pairs of tarsi 5-jointed, posterior tarsi 4-jointed ; 

 anterior coxae globose, ovate or conical, not transverse, contiguous or 

 slightly distant at apex, posterior, as a rule, mobile; eyes usually kidney- 

 shaped ; maxillary palpi exserted, usually clubbed ; antennae usually 

 moniliform and not geniculate ; mandibles almost always bifid at apex ; 

 elytra entire, very rarely shorter than the abdomen ; abdomen composed 

 of five, very rarely six, ventral segments : epimera of mesothorax, as a 

 rule, reaching intermediate coxae. It will be seen from this account of 

 the characters that there is not one, except the first, that is not liable to 

 exceptions', and the first, as has been stated above, is found in other 

 groups ; it is therefore very difficult to determine the true position of 



VOL. v. B 



