OCR Text |
Show 388 INSECTA. The eighthtribe,thatofthe. Bvnnnn, differsfromthep. 1 . re ceding in the perfect contract1 1ty of the legs; the tibim are susceptible of being flexed on the thighs, and the tarsi on the tibim(l ), so that when thus folded and pressed against the body, the animal seems to be inanimate and entirely destitute of feet. The tiuiro are usually broad and compressed. The body is short and convex. This tribe is chiefly composed of the genus Bvninius, Lin. Those species which form the N osonENDRON, Lat. Are removed from the others by their entirely exposed, very large and scutifot·m mentum. Their antenn::e tet·minate abruptly in~ short, perfoliaceous and triarticulated club. They are found in wounds of trees, of the Elm particularly(2). BYRRHus, Lin.-Cistela, Geoff. The tt·ue Byrrhii difftr ft·om the preceding Insects in their men· tum, which is of an ordinary size and interlocked (at least partially) by the pre£sternum, whose anterior extremity is dilated. In some, the antenn<£ enlarge insensibly, or terminate in an elon· gated club formed of from five to six joints. B. pilula, L.; Oliv., Col. II, 13, 1, 1. From three tofour lines in length; black beneath, blackish-bronze or soot-colour and silky above, with little black spots mingled with lighter ones arranged in lines. M. Waudouet• has detected the larva of a variety of thisspe· cies. It is narrow and elongated; the head thick; the plate of the first segment lat·ge, and the two last longer than the others. It lives in Moss. A second species-striato-punctatus, Dej.-with similarly formed antennre, constitutes a separate division, on account of its tarsi, of which the fourth joint is vel'y small and concealed between the lobes of the preceding one. The antennre of another species, very small and covered with (I) In the Anthreni all the tibire fold against the poste1·ior side of the thighs; but in the others, the two that are anterior are flexed towards the head, and the other behind. t2) Lat., lb., II, p. 43; Oliv., Encyc. Method., article Nosodendre. COLEOPTEUA. 389 hairs, tet·minate in a triarticulated club. It forms the genus TRtNODES, Meger!., and Dej .( l) On similal' grounds we might also separate ft·om the Byrrhii some other analogous species(2), in which the antennal club consists of but two joints, the last much the thickest and nearly globular. All the Byrrhii remain on the ground in sandy localities(3). It is impossible to describe the Clavicornes of our second section, although a very natural one, but by the reunion of several characters. Some of these Insects are removed from all others of the family by their antennre, which consist of nine or six joints; they are those, which, in this respect, seem to approximate most closely to the Palpicornes. The antenn~ of the other Clavicornes of the same section are composed of eleven or ten joints ; but sometimes they are not much longer than the head, and from the third joint form an almost cylindrical or fusiform club, arcuated and somewhat serrated; sometimes they are nearly filiform and as long as the head and thorax united; but here, as in most of the other subgenera of the same division, the tarsi are terminated by a large joint furnished with two strong terminal hooks. Those of someHete1' ocerus, Georissus-consist of but four joints. The body of these Insects is generally ovoid, and their head plunged to the eyes in a trapezoidal thorax, with a recurved lateral margin, and terminating posteriorly in acute angles; the prmsternum is dilated anteriorly( 4 ), and the legs are imperfectly contractile. They are found in the water, under stones in the vicinity of shores, and frequently in the mud: some of them-Dryops--are allied to the Gyrini by the structure and shortness of their antennre. (1) .B.ntltrenus ltirtus, Fab.; Panz., Fann. Insect. Germ., XI, 16. (2) ByrrhuiJ erinaceus, Zicgl.;-B. sctiger, Illig. (3) For the other species see Fabricius, Olivier, Schrenherr, Gyllenhal, &c. The genus Mumunrus, ~each, according to that gentleman, belongs to this tribe. The antennre at'e composed of but ten joints, the last of which forms an ovoido.globular club. See Lin. Trans., XIII, P· 41. (4) The Potamophili excepted. |