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Show 442 INSECTA. W c will divide this section into four great families(l ), the two first of which are somewhat analogous to the first pentamerous Coleoptera, in an excrementitious appamtus discovered in several of their genera by the same savant; their chylific ventricle also is frequently covered with papillre. In several of these Insects, we find the vestiges of another secreting apparatus but seldom observed among Coleoptera, that which is denominated the salivary apparatus. The hepatic vessels, as in the Pentamcra, with but few exceptions, are six in num. bcr, and have two insertions distant from each other: "at one extremity," says M. Dufour, " they are inserted by six in. sulated ends round the collar, which terminates the chylific ventricle ; the other opens into the origin of the crecum by trunks, varying in number according to the family and genus." In some, where the elytra arc generally solid and hard, and the hooks of the tarsi are almost always simple, the head is ovoid or oval, susceptible of being received posteriorly into the thorax, or sometimes narrowed behind, but not abruptly, and without a neck at its base. Many of these Heteromera avoid the light. This division will comprise the three fol· lowing families. FAMILY I. MELASOMA. This family consists of unmixed black or cinereous coloured Insects, (from which is derived the name of the division,) mostly apterous, and frequently with soldered elytra. Their antennro, entirely or partly granose, almost of equal thickness throughout or slightly inflated at the extremity, and the third joint wholly elongated, are insert under the projecting edges of the head. The mandibles are bifid or emarginated at the extremity; the inner side of their maxillm is furnished with a (1) In a natural order, the fourth is connected with the first by the Helopii which Linn zeus places in his genus Tenebrio. It is also evident that the Tenebrios lead to Phaleria, Diaperis, &c., or to our second family. COLEOPTEUA. 443 corneous tooth or hook, all the joints qf the tarsi arc 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 toM. Dufour-Ann. des Sc. Nat., V, p. 276- the biliary vessels are inserted into the inferior face of the mecum by a single trunk, resulting from the confluence of two very short branches, formed by the union of three biliary vessels. The bile is yellow, sometimes brown or violet. The alimentary canal-Ann. des Sc. Nat., III, p. 478-is long, and its length in our first tribe, or the Pimeliarire, is thrice that of the body; the esophagus 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 pectus; it is marked internally with longitudinal plicre or fleshy columns, terminating in some-Erodii, Pimelim-ncar the chylific ventricle, at a valve formed of four principal corneous, oval and connivent parts; the chylific ventricle is elongated, flexuous or doubled, most commonly covered with little papillre resembling projecting points, and terminated by a small collar, callous within, which receives the first insertion of the biliary vessels. The same anatomist has observed in some subgenera of this family-BlajJs, .!lsida-a salivary apparatus, consisting of two floating vessels or tubes, sometimes perfectly simple-.!lsida-and at others irregularly ramousBlaps ;-he is also convinced that they exist in the other Pimeliarire. M. Marcel de Serres-Observations sur les usages des diverses parties du tube intestinal des Insectes, Ann. du Mus. d'Hist. Nat.-has carefully studied the texture of the tunics of the alimentary canal(l ). The adipose tissue is more (1) What M. Dufour styles the chylific ventr·icle, M. de Serres calls the stomach, and relative to other Insects the duodenum. What he calls the small intestine is considered by the fhst as the crecum. According toM. nufour·, M. M:. de Serres has not mentioned the crop of the Melasomn, although in A kir; and Pimeli:t it inery apparent. |