OCR Text |
Show 374 INSECTA. rather in the form of a reversed cone than cylindrical, and finall in which the mentum is slightly emarginated, willre-ente1· the su~: genus HxsTER, properly so called. Some species in which, as in the Ilololeptre, the fout• posterior tibire have but a single l'ant;e of small spines, and that also live under the bark of trees, constitute the genera PLATYSOMA and DENDROPH!· LUS of Leach. The fhst(l) only differs from the second(2) in the flattening of the body above, and in the shortening of the thorax which is also narrowed anteriorly. A species of the same division' J JL proboscideus, Payk., Monog., VIII, 4, has a peculiar form. The body is long and narrow, and the thorax more than half as long again as it is wide. The remaining Histeroides have two ranges of spines on the four poste1·ior tibire. They are the only ones which Dr Leach retainsin the genus Hister. Jl unicolor, L.; Payk., lb., II, 7. Four lines in length; entirelv black and glossy; three dentations on the exterior side of the t.wo first tibice; two strire on each side of the thorax, and four on the external part of each elytron, that nearest the margin in· terrupted. Very common. The number of tibial deutations, that of the strire on the thorax and elyt1:a, their punctures, and the form of the body, have furnished M. Paykull with excellent characters, by means of which he has well described the species. A last subdivision of this tribe comprises very small Histeroides, with a thick and almost globular body, of which the but slightly or not at all laterally compressed pr<esternum does not advance over the mouth, and is st1·aight in ft·ont. In some-AnnJEus, Leach-it is prolonged to the anterior angles of the thorax, and entirely covers the antennre when they are con· tractecl; in the others-ONTIIOPIIJLus, Leach-it is narrower; hut here the antennal club is received into a very distinct orbicular cavity, situated under the anterior angle of the thorax. The ante· rior tibi<e are frequently narrow, almost linear, and edentated. The last superior semi-segment of the abdomen is curved inferiorly, and appears to terminate it(3). (1) Histerpicipes, Fa.b.; Payk., lb., VIll, 5;-H.jlavicornis,Id., VITI, 6;-H.ob· longus, ld., X, 3. (2) .B.. punctatus, Id. VII, S. (3) The H. globoau8, Pa.yk., VIII, 2, is referred by Leach to his genus Abr~, and also the H. minutm, Id., VIII, 1; to his Onthopltilu1, he refers the Hzll· COLEOPTERA. 375 The legs of the other Clavicornes are inserted at an equal distance from ear.h other. Those in which these organs are not contractile, and the tat·si at most can only be flexed on the tibire, whose mandibl~s arc most commonly salient and flattened or not thick, and whose prresternum is never dilated ante. riorly, will constitute five other tribes. In the third tribe of this family, that of the SILPIIALES, we find five distinct joints in all the tarsi, and the mandibles terminating in an entire point without emargination or fissure( I). The antennre. terminate in a club that is most commonly per4 foliaceous and consisting of from four to five joints. The internal side of the maxillm, in most of them, is furnished with a horny tooth. The anterior tarsi are frequently dilated, at least in the males. The exterior margin of the elytra of the greater number is marked by a groove with a well raised border. This tribe is composed of the genus StLPIIA, Lin.-Peltis, Geoff. Here the a.ntennre arc suddenly terminated by a short ancl solid club, formed by the four la~t joints; the second is la.rger than the following ones. The body is almost square, the elytra are trunca,ted, the tibi;-e dentated, the tarsi simple, and the mandibles bidentated on the inner side; the last joint of the maxillary palpi is as long as the two preceding ones taken together. The1·e is a horny tootl~ on the inner side of the maxillre. So closely do these Insects resemble the Histeroides, that Fabricius confounded them. Such are th'ose which form the SPHJERITEs, Dufts.-Sarapus, Fisc h.-/lister, Fab. -Nitidula, Gyl· len. (2) Here, the antennre terminate in a perfoliaceous club. 1lriatua, Payk., lb., XI, 1 ;-ll sulcatus, X, 8;--the hispidua, Id., XI, '2, appears to be congeneric. The genus Ceutocerua of Germ:u·, Insect. Spec. Nov., I, p. 85, l, 2, from the form of the a.ntenncc, legs, &c., would naturally seem to come after the Hiateroides, hut the elytra cover the abdomen and the mandibles are not salient. 1 have never seen a specimen of this genus. (1) Dentations however are sometimes found on the internal side, as in Sphzrites. (2) Dufts., Faun. Aust., I, p. 206; Hiater glabratus, Fa.b.; Sturm, I, xx; &rapm, Fisch., Mem. of the Soc. of Nat of Moscow. |