| OCR Text |
Show 324 INSECTA. HYGROBIA, Lat.-Hydrachna, Fab. Clairv.-Pmlobius, Schcenh, The tarsi also composed of five distinct joints, the four anterior of which are almost equally dilated at base, in the males, into a little palette forming a long square; but the antennre a1·e shorte1• thantn head and thorax; the body is ovoid and very thick in the middle~ eyes prominent(!). ' H YDROPORus, Clairv .-Hyphydrus, Schrenh. The four anterior tarsi nearly similar, and spongy underneath in both sexes, composed of but four distinct joints, the fifth being 1de. flcient Ol' very small and concealed, as well as a part of the last, in a deep cleft in the third. These Insects have no apparent scutellum(2). We might separate from them some species(3) in which the bodr is almost globular, and where the last joint of the fout· anterior tarsi is very small , and projects but little beyond the preceding one-Hy. phydrus, Lat.-The body of the rest is oval, and not so thick(4). Sometimes the antennre are slightly dilated and wider in the mid· die of their length; the last joint of the labial palpi is emarginat~ and appears forked. Add for the American species of Colymbetes the C. erythropterus, fenulrali!, ambiguus, seriatus, nit-idus, bicarinatus, venustus, glyphicus, obtwatus, &c. Of the G. Lacophilus we have the L. maculosus and proximus. .O.m. Ed. (1) Hydraclma Hermanni, Fab.; Lat. Genet'. Crust. et Insect., I, vi, 5; Clairv., Entom. Helv. II, xxvii, A, a;-IL uliginosa, Clairv., lb. B, b. These Insects with the Halipli, in the system of Leach-Zoot Miscell. p. 68- form a particular group, the characters of which are : a scutellum; all the legs adapted for walking, with five joints to all the tarsi and two terminal hooki to the last. The Hygrobire have their exterior palpi somewhat enlarged at the end; two stout and approximated spurs at the extremity of the tibire, and their anterior tarsi susceptible of being doubled under the tibire to which they are annexed. (2) In the preceding divisions, some small species excepted, it is very apparent. Add. of American species the Hydrop. undulatus, oppositus, niger, catascopium, lacustns, parallelus, undulatus, &c. .O.m. Ed. ( 3) The Hyd. gibba, ovalis, scripta, Fab.; Hyphydrus lyratus, Schrenh., Synon. Insect., II, iv, 1. ( 4) The Dytisci inaJqualis, reticulatus, conjluens, picipes, pictus, geminua, lintAtus, halensis, duodecim-pustulatus, dm·salis, sexpustulatus, palustris, depres8U8, /i/1} ratus, planus, erythrocephaJus, nigrita, granularis, Fab. See Schrenherr, Synon. Ins~ct. II, genus Hyphydrus.--Panz., Index Ento:m., genus Hydroporw;-and Clatrv., Entom. Helv. II, the same genus. COI~EOPTERA . 325 NoTEuus, Clairv. No scutel; tarsi consisting of five distinct joints, and the two first of the four anterior dilated in the males, forming an elongated palette · first joint of the two anterior tarsi covered by a broad laminifor~ spu1·, the part of the pectus bearing the last legs with a deep groove on each side( 1 ). The others have but ten distinct joints in their antennre; their exterior palpi are fusiform, or have a more slender termination tapering to a point, and the base of the posterior legs is covered with a large shield. The body is convex and ovoid underneath, as in Hygrobia; but there is no scutel, and all the tarsi are filiform, composed of five almost cylindrical joints, and have nearly the same form in both sexes. They are the HALIPLus, Lat.-Hoplitus, Clair.-Cnemidotus, Illig.(2) The second genus of the Hydrocanthari, or the GvRINus, Lin. Comprises those in which the antennc:e are clavate and shorter than the head; the two first legs are long and project like arms; the remaining four are compressed, wide, and pinnate. There are four eyes. The body is oval and usually very glossy. The second joint of the antennre, which are inserted in a cavity before the eyes, is prolonged exteriorly in the form of an auricle, and the following joints(3) at•e very short, crowded, and united in one almost fusiform and slightly curved mass. The head is sunk in the thorax almost to the eyes, which are large, and divided by a border, in such a way that two are above and two underneath. The labrum is rounded and strongly ciliated before. The palpi are very small, and the interior of those attached to the maxillre are wanting, or are not developed in several, and particularly the larger species. The thorax is short and transversal. The elytra are obtuse and truncated at their posterior extremity, leaving the anus exposed, which ends in a (1) Dytiscus crassicornis, Fab.; Clairv., Entom. Hel\1'., II, xxxii. (2) The Dytisci fulvus, impressus ami obliquus, Fab. See Latr., Gener. Crust. et Insect., I, p. 234; Clairv., Entom. Helv., II, genus Hoplitus, XXXI; Panz., Tnd. Entom., genus id., and Schrenerr, Synonym. Insect. II, genus Cnemidotm. {American species, Hal. 12-punctatw, triopsis, &c. .O.m. Ed.] (3) But seven are distinctly visible, the first and Jast of which are the longest. |
