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Show 390 INSECTA. I will divide this section into two tribes( 1). The Insects which compose the first or the AcANTHOPODA are remarkabi for their flattened and tolerably wide tibire, armed anteriorle with spines; for their short quadriarticulated tarsi, the hoo~ of which are of th: u~ual size; and for their depressed body. The prresternum IS dilated. The antennro arc a little longer than the head, arcuated, and formed of eleven joints, the last six constituting an almost cylindrical and slightly serrated club; the second is short and not dilated. This tribe is composed of the single genus HETEROCERus, Bose. Fab. These Insects are found in the sand or mud, along the borders of rivulets, marshes, &c., issuing from their holes when disturbed by the trampling of feet. The form of their tibire enables them to turn up the earth, and conceal themselves in it; their tarsi can be flexed upon the tibire. There also reside their larvre, which were first discovered by M. Miger. H. marginatus, Fab.; H. lrevigatus, Id.; Panz., Faun. Insect., Germ., XXIII, 12. A small, blackish, and silky Insect, with little yellowish or reddish spots, varying in form and number . . ' and somettmes even wantmg on the elytra. M. Gyllenhal observes that the tarsi really consist of five joints, the first of which is small and oblique. See Insect. Suec. I, p. 138. The second tribe, or that of the MACRODACTYLA, com· prises Clavicornes with simple, narrow tibire and long tarsi, all-one genus excepted ( Georissus), well distinguished from every other of the tribe, by its antennre of nine joints, of which (1) We might also divide the section in the following manner. I. Antenna: composed of eleven joints. A. Antenna: clavate and very short. a. Tibia: spinous; tarsi quadri·articulated. HETEROCERUS. b. Tibia: simple; five joints in the tarsi. PoTAliiOPHILUs. DnYo.Ps. B. Antenna: filiform or slightly enlarged near the end, as long as the head and thorax. ELEMIS. H. Antenna: nine or six joints. MACRONIOJiUS. GEORISSUS. COLEOPTERA. 391 the three last form an almost solid club-composed of five distinct joints, the last _of w~ich is large, with two stout terminal hooks. The body IS tlnck or convex. The thorax is less rounded, and most commonly terminates on both sides in acute angles. The principal type of this tribe is the genus DRYOPs, Oliv., Or that of Parnus, Fab., which is divided in the following manner. 1• Those whose antennre, never much longer than the head, are composed of from ten to eleven joints, which, from the third, form an almost cylindrical or slightly fusiform club, arcuated, and somewhat serrated. PoTAMOPHIT.us, Germ.-Parnua, Fab. The Potamophili, which, ignorant of the establishment of this subgenus, we had named HYDERA(I), have their antennre exposed, and not received into particular cavities; they are rather longer than the head; the first joint is almost as long as the following ones taken together, and the second short and globular. The palpi are salient, and the mouth is completely exposed as the prresternum does not project over it, a character in this tribe exclusively peculiar to this subgenus(2). DRYOPS, Oliv.-Parnus, Fab. In Dryops proper, the antennre, shorter then the head, are received into a cavity situated under the eyes, and are almost covered by the second joint, which is large, dilated, in the form of an almost triangular palette, and projects in the manner of an auricle, whence the name of Dermeste a oreilles, given to the most common species by Geoffroy(3). The pal pi are not salient. 2. Those in which the antennre, composed of eleven joints, are filiform, or merely a very little thicker near the extremity, and at least nearly as long as the head and thorax. (1) Regn. Anim., Ill, p. 268. ('2) Parnus acuminatus, Fab.; Panz., Faun. Insect. Germ., VI, 8;-Dryop• picipes, Oliv., III, 41, 1, 2. (3) Latr., Gen. Crust. et Insect., II, 55; Schamh, Synon. Insect., I, ii, P· 116. The Dryops Dumerilii presents some differences in the length of the legs, the form of the antenna: and thorax, which have induced Doctor Leach to form a separate genus-Dryops-for it. The other species re-enter Pamua. |
