OCR Text |
Show 262 INSECTA. metathorax, is united to the abdomen and confounded with it. M. Kirby was the first, I think; who thus designated this segment; but Nitzsch, on the other hand, seems to have first employed the others(l). The limits of this work i.nterdict any exposition of the subgenera he has established. We w11l mer:ly rcmar~ that the one he calls Goniodcs, the fourth subgenus of Plulopterus, lS exclusively proper to the Gallinace~. In the. collection of ~emoirs which ter. minates our Histoire des Foul'lms, we have nunutely described a species of Ricinus-Philoptcrus, Nitz.sch.' . . M. Leon Dufour, with the P. meltte::e of K1rby, previously well observed by De Geer, who considered it as the larva of the Meloe proscarabmus, as well as by that celebrated entomologist, has formed a new genus-Triongulin des andrenettes-the characters of which he has figured and published in the Ann. des Sc. Nat. XIII, 9, B. If this Insect be not the larva of that Meloe, as in the opinion of M. Kirby, there is no doubt but that it forms a peculiar subgenus in the order of the Parasita; but according to the researches of MM. Le. peletier and Servile, the idea of De Geer is confirmed. ORDER IV. '• SUCTORJA(2). The Suctoria, which constitute the last order of the Ap. tera, have a mouth composed of three(3) pieces, enclosed between two articulated laminre, which, when united, form a cylindrical or conical proboscis or rostrum, the base of which is covered by two scales. These characters exclusively dis. tinguish this order from all others, and even from that of the Hemiptera, to which, in these respects, it approximates the most closely, and in which these Insects were placed by Fabri· cius. .The Suctoria, besides, undergo true metamorphos~, analogous to those of several Diptera, such as the Tipulre. ( 1) See our general observations on the class of Insects. (2) Siphonaptera, Lat. (3) Rresel represents but two; Kirby and Straus, however, have observed one more. According to the latter, the two scales which cover the base of the ro~ trum are palpi. . SUCTORIA. 263 This order consists of a single genus, that of PULEx, Lin. Th body of· the Flea is oval, compressed, in ·ested by a firm skin, andedivided into twelve segments, three of which compose the trunk, that is short, an(l the others the al?domen. The head is small, strongly om ressed, rounded above, and truncated ami ciliated before; it is ~urnished on each side with a small rounded eye, behind which is a fossula, in which we discover a little movable body furnished with small spines. At the anterior margin, near the ol'igin of the rostrum, arc inserted the pieces considered as the ante~nre; they are scarcely the length of the head, and ~re composed of four almost cylindrical joints. The sheath or rost1·um ~s divided into three segments. The abdomen is very large, each of its annuli being divided intq or forming two laminre, one superior and the other inferior. The legs are strong, the last ones particularly, fitted for leaping, spinous, the coxa and femur large, the tarsi composed of five joints, the last terminating in two elongated hooks; the two anterior legs are inserted almost under the head, the rostrum being placed midway between them. The male, in coitu, is placed under the female, so that they face each other. The latter lays a dozen of white and slightly viscid eggs; the larvre have no feet, are much elongated, resemble little worms, and are extremely lively, rolling themselves into a circle or spirally, and crawl with a serpentine motion; they are first white and then reddish. Their body is composed of a scaly head, wit~out eyes, bearing two very small antennre, and of thirteen segments, with little tufts of hairs, the last one terminated by two kinds of hooks. S~me small movable pieces are observed in the mouth, by which these larvre push themselves for~vards. After remaining twelve days under this form, they enclose themselves in a little silky cocoon,in which they become pupre, and from which, in about the same time, they issue in their perfect state. Pulex irritans, L.; R~s., Insect., II, ii, iv. The common Flea feeds on the blood of Man, the Dog, Cat, &c.; the larvre live in the dirt that is collected under the nails of filth.y individuals of the human family, in the nests of Birds, particularly of Pigeons, where they fasten to the neck of their young, and suck their blood to such a degree as to become perfectly red. Pul. penetrans, L.; Catesb., Carol. III, x, 3(1). This sp~cies, . (1) M. Dumeril has given an excellent figure of this animal in his work, Con$ ld. Gen. sur Ia Classe des Insectes, and in the Diet. des Sc. Naturelles. |