COBMOP TE EA: 
HETEROMERA. 
Auruoucy 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, Anisotoma, Acritus, 
the male of Rhizophagus, &c., so that the character by no means holds 
good in all cases, and there is no other upon which it can be strictly de- 
fined ; 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 introdueed 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 Rhinosemus resembles 
certain Curculionids, while Diaperis and Platydema might be taken for 
Chrysomelide, and Gidemera, Nacerdes, Lytta, and Pyrochroa for Ma- 
lacodermata; Tribolium again appears to be allied to the Cryptophagide, 
Hypophiwus to the Colydiide, and certain species of Cistela 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 Metacus. 
The following are the chief characters of the division as given by 
Thomson :—Anterior pairs of tarsi 5-jointed, posterior tarsi 4-jointed ; 
anterior coxe 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; antenne 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 coxe. 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 
