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Show 32 INSJ:o:CTA. The two anterior legs, as well as in the following subgenus, act as pincers. VELIA, Lat. Where the antennre are also filiform, but the sheath of the sucker has but two apparent joints, and the legs, much shorter, are inserted at nearly equal distances from each other(l). FAMILY II. HYDROCORIS£. In our second family of the Hemiptera, the antennre are in· serted and concealed under the eyes ; they are shorter than the head, or hardly as long. All these Insects are aquatic, carnivorous, and seize others with their anterior legs, which :flex on themselves and act as pincers. They sting severely. Their tarsi present but one or two joints. Their eyes are in general remarkably large. Some-Nepides-have the two anterior legs in the form of pincers, composed of a thigh, either very thick or very long, with a groove underneath for the reception of the inferior edge of the tibia and of a very short tarsus; or one that is even confounded with the tibia, and forming with it a large hook. 'fhe body is oval and much depressed in some, and linear in others. They form the genus N~PA, Lin. Or that of the Aquatic Scorpions, as they are commonly called, which is thus divided: GALGULus, Lat. Where all the tarsi are similar, cylindrical, and composed of two (1) Lat., Gener. Crust. et Insect., III, p. lSI. HEMIPTERA. 33 very distinct joints, the last with two terminal hooks. The antennre appear to consist of but three joints, the last of which is the largest and ovoid( 1 ). The antennre of the following genera are quadriat·ticulated, and the antel'iot· tarsi terminate simply in a point or hook. NAuooRis, Geoff. Fab. The labrum in N aucoris is not emarginated, as is the case in the following genus, but is exposed, large, triangular, and covers the base of the rostt·um. The body is almost ovoid and depressed, and the head rounded; the eyes are very flat. The antennre are simple and without any projection in the form of a tooth. There is no salient appendage at the postet·ior extremity of the abdomen. The fout· last legs are ciliated, and their tarsi consist of two joints, with two hooks at the end of the last. N. cimicoides; Nepa cimicoides, L.; Rres., Insect., III, Cim. ~quat., xxxviii. Five or six lines long, and of a greenish brown, hghter on the head and thorax; margin of the abdomen serrated and projecting beyond the elytra(2). In th.e three following subgenera, the labrum is sheathed, and the extremity of the abdomen presents two filaments. BELosTOMA, Lat. Where all the tarsi are biarticulated, and the antenn::e are semipectinated( 3). NEPA, Lat. Or Nepa proper, where the anterior tarsi have but one joint, and the four posterior ones two, and where the antennre appear forked. The rostrum is c~rve~ beneath; t~e cox<e of the two anterior legs are short, and their thighs much wider than their othet· parts. Their body is narrower and more elongated than in the preceding subgenera, a~d almost elliptical. Their abdomen is terminated by two ~e.t::e which enable them to respire in the oozy and aquatic locahttes at the bottom of which they live. Their eggs resemble the seed of a plant of an oval figure, crowned with a tuft of hairs. (1) Lat. lb., HI, p. 144; Nauoori8 oculata, Fa b. (2) Fab., Syst. Ryng.; Lat., Gener. Crust. et Insect., Ill, p. 146. (3) Lat., lb., p. 144; the Nepa grandis, annulata, rustica, Fab. VoL. IV.-E |