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Show 48 INSECTA. pie eyes are situated between them or 1a tera ll Y( I) ' but not near the front. . f These Insects are also close] y allied to the J ass1 by the extent 0 their laminre situated along the sides of the hood, and the length of the terminal 'seta of the antennre; it appears to be articulated at base as in the Cicci, from which they almost only differ in the form of the thorax(2). FAMILY II. APHID II. The ·second family of the homopterous Hemiptera, or ·the fourth of the order, is distinguished from the preceding one by the tarsi, which are composed of but two joints, and by the filiform or setaceous antennre, which are longer than the head an<.l have from six to eleven joints. Those individuals which are winged always have two ely· tra and two wings. · • These Insects are very small; their body is usually soft, and their elytra are nearly similar to the wings, or only differ from them in being larger and somewhat thick. They are astonishingly prolific. Here the antennre are composed of from ten to eleven joints, the last of which is terminated by two setre. They possess the faculty of leaping, and form the genus PsYLLA, Geoff.-Chermes, Lin. These Hemiptera, also called pseudo-aphides, or faux-pucerons, live on the trees and plants from which they derive theit· nourish· ment; both sexes are furnished with wings. Their larvre usually (1) Some species, such as the Oercopis grisea, transversa, striata, &c., Fab., on account of their flattened head furnished neat• its edges with simple eyes, should apparently be formed into a separate subgenus. (2) Germar, Magas. der Entom., IV, p. 58, genus Tettigonia, Fab., Syst. Ryn· got., p. 61. 111-:MI PT EH.A. 49 have a very flal body, broad head, and the abdomen rounded posteriorly. 'rheir legs are terminated by a little membranous vesicle accompanied bepeath with two hooks. Four wide and fiat pieces, which are the sheaths of the elytt·a and ~vings, distinguish the nymph. Several in this state, as well as in the first, are covered with a white substance resembling cotton, ananged in flakes. Their freces form threads or masses, of a gummy and sacchal'ine nature. Some species, by wounding plants in ordet· to suck their juices, produ?e excrescences somewhat resembling gall-nu~s, particularly on then· leaves or buds. Of this number is the P. buxi; Chermes buxi, L.; Reaum., Mem., Insect., III, xix, 1, 14. Green, with brown-yellowish wings. Other species are also found on the Alder, Fig tree, Nettle, &c.( 1) A species which lives in the flowers of the rushes has been erected into a genus by Latreille, under the name of LIVIA. The an· tennre are much thicker inferiorly than at their ext1·emity(2). · The remaining Aphidii have but six or eight joints in the antennre ; the last is not terminated by two setre. _Sometimes the elytra and wings are linear, fringed with ha1:s, a~d extended horizontally on the body, which is almost cyhndr1~al; the rostrum is very small or but little distinct. The tarsi are terminated by a vesicular joint without hooks. The antennre consist of eight graniform joints. Such are the Insects which f'orm the genus THRIPS, Lin. Th~y ~re extremely agile, and seem to leap ratl1e1· , than fly. vVhen we 1rr1~ate them. beyond a certain point they turn up the posterior extremtty of the1r body in the manner of the Staphylini. They Iiv·e on flowers, plants, and under the bark of trees. The Jai·gest species scarcely exceed one line in length(3). · (1) See Fab., Geoff., De Geer. (:)~at., Gen. Crust. et Insect., III, p. 170; Arb., Faun. Insect., VI, 21. f ( ) ee Lat., Ibid., P· ead., and the authors already quoted. In the organization ~ the mouth, I have detected characters which seem to distinguish it essentially r?m that of I~sects of this order. M. Straus, who has studied it with admirable mmutenes&, tlunks that Thrips belong to the order of the Orthoptera. · VoL. IV.-G |
