OCR Text |
Show 392 INSECTA. ELMIS, Lat.-Limnius, Illig. They are found in water, under stones, or on the leaves of the Nymphrea(l). 3, Those in which the always very short antennre consist of but six or nine joints, and terminate in an almost solid, oval, or nearly globular club. MAoRONYonus, MUll. Germ. These Insects have five distinct joints in the tarsi, an oblong body, and antennre of six segments, the last of which-perhaps composed of three-forms an oval club; they can be folded under the eyes(2). GEoRissus, Lat. Gyll.-Pimelia, Fab. Here the tarsi consist of but four joints; the body is short, turgid and almost globular, and the abdomen embraced by the ely. tra; the antennre are composed of nine joints and terminate in a round club formed by the three last(3). FAMILY V. PALPICORNES. In our fifth family of pentamerous Coleoptera, as in the fourth, we observe antennre terminating in a club, usually perfoliaceous, but consisting of nine points at most in all, and inserted under the lateral and projecting edges of the head; they arc never much longer than the latter and the maxillary palpi, and frequently even shorter than the last mentioned organs. The mentum is large and scutiform. The body is usually ovoid or hemispherical, convex or arched. The legs in several are adapted for natation, and then consist of but four very distinct joints, or of five, the first (1) Latr., lb., TI, p. 49; Schrenb., lb. J, ii, p. 117; Gyllenh., Insect. Suec. I, p. 551. (2} Macronychus quadrituberculatus, MUll.; Illig., Mag., V; Lat., Gener. Crust. et Insect., It, p. 58; Parnus obacurus, Fab.; Germ., Insect. Spec. Nov., J, P· 89. (3) Pimelia pygmrea, Fab ., Georissus pygrn::eus, Gyll ., Insect. Suec., T, iii, P· 675; Tt·ox dubius, Panz., Faun. Insect. Germ. LXII, 5. COLEOPTEU.A. 393 of which is much shorter than the second; all the joints are entire. Those in which the legs are natatory, the first joint of' the tarsi is much shorter than the following ones, and the maxillre are entirely corneous, will form our first tribe, that of the HvnROPIIILII, which embraces the genus HYDIWPHILus, Geoff. Linnreus merely made these Insects a divisiC?n (t,he first) of his genus Dytiacua, but their anatomy is essentially different. The alimentary canal of the Hydrophili is very analogous in its contexture and length, which i;; mor·e than four or five times that of the body, to that of the Lamellicornes, and only approximates to the same canal of the carnivorous Insects with respect to the biliary vessels. They neither have the natatot·y bladder nor excrementitious apparatus which characterize the Hydrocanthal'i. In the females only, this appara· tus is replaced by organs which secrete the matter that is to form the cocoon that encloses the ova, and to produce it their anus is furnished with two fusi. Finally, the inale ot·gans of generation have the closest affinity .with those of the Clavicornes(l). In some, where the body is oval, oblong and depressed, or elongated and nal'fow, the thot·ax scabrous and narrowed posteriol'ly, the tibire are slender and fur·nished with small sput·s, and the tarsi filiform, slightly ciliated and terminated by two strong hooks; the antennre-always composed of nine joints-terminate in a slightly · perfoliaceous or nearly solid club, almost in the form of a reversed cone, and the extremity of the mandibles is entire, or ends i,n a ' single tooth. They are all very small, swim but seldom or badly, and inhabit stagnant waters, from which they occasionally remove, to conceal themselves under stones or in the earth. They compose the family of the Helophoridea of Leach, a name which reminds us of the genus Elophorus of Fabricius. ' ' Here the length of the maxillary palpi does not surpass that of the antenure or is even less. The epistoma is entire or without anr notable emargiuation. Sometimes the maxillary pal pi are terminated by a thicker and oval joint. ' (I) "The conformation and structure of the male organs of generation in the Palpicornes fully justify the position in the entomological series, asaigned to them by H. La.treille."-Leon Dufour, Ann. des Sc. Nat., VI, P· 172. VoL. UI.-2 Z |