<38 INSECTA. 



narrowed behind, but not abruptly, and without a neck at its base. 

 Many of these Heteromera avoid the light. This division will com- 

 prise the three following families. 



FAMILY I. 



MELASOMA. 



This family consists of unmixed black or cinereous coloured In- 

 sects, (from which is derived the name of the division,) mostly apte- 

 rous, and frequently with soldered elytra. Their antennae, entirely 

 or partly granose, almost of equal thickness throughout or slightly 

 inflated at the extremity, and the third joint wholly elongated, are 

 inserted under the projecting edges of the head. The mandibles are 

 bifid or emarginated at the extremity; the inner side of their maxillae 

 is furnished with a corneous tooth or hook, all the joints of the tarsi 

 are entire, and the eyes oblong and but very slightly prominent, a 

 circumstance which, according to M. Marcel de Serres, indicates 

 their nocturnal habits. Almost all these Insects live on the ground, 

 either in sand, or under stones, and frequently in cellars, stables, and 

 other dark places about our habitations. 



According to M. Dufour — Ann. des Sc. Nat. V. p. 276 — the biliary 

 vessels are inserted into the inferior face of the caecum by a single 

 trunk, resulting from the confluence of two very short branches, 

 formed by the union of three biliaiy vessels. The bile is yellow, 

 sometimes brown or violet. The alimentary canal — Ann. des Sc. 

 Nat., Ill, p. 478— is long, and its length in our first tribe, or the 

 Pimeliariae, is thrice that of the body ; the oesophagus is long and 

 leads to a crop smooth or glabrous externally, that is more developed 

 in these latter Insects where it forms an ovoid sac lodged in the pec- 

 tus ; it is marked internally with longitudinal plicae or fleshy co- 

 lumns, terminating in some — Erodii, Pimelice — near the chylific ven- 

 tricle, at a valve formed of four principal corneous, oval, and conni- 

 vent parts ; the chylific ventricle is elongated, flexuous or doubled, most 

 commonly covered with little papillae resembling projecting points, 

 and terminated by a small collar, callous within, which receives the 

 first insertion of the biliaiy vessels. The same anatomist has ob- 

 served in some subgenera of this family — Blaps, Asida — a salivary 

 apparatus, consisting of two floating vessels or tubes, sometimes per- 

 fectly simple — Asida — and at others irregularly ramous — Blabs ; — 

 he is also convinced that they exist in the other Pimeliariae. M. 

 Marcel de Serres — Observations sur les usages des diverses parties du 



