490 IXSECTA. 



or conical, the liasc of nliicli is covcreil by two scales. TLcsc cliaracters exclusively distin- 

 guish it from all other insects, mclnihng the Ileniiptera, with which it was ranged by Faliricins. 

 The Suctoria, moreover, nndergo real metamoriihoses, analogous totliose of m, any two-wnis-cd 

 insects, as the Ti]ndid;r. 



This ftrilcr is coinposed of the single genus of Fleas^ — 



PuLEX, Linn. 

 The body is oval, comiiresscd, inclosrd in a tough skin, anil divided into twelve segments, of which 

 three comiiose the trunl;. whieii is sleirt, and tlie otliers the ahdenien. Tlie head is small, very com- 

 pressed, rounded ahovc, Irumalc, ami ciliated in frniit. It has, on each side, a smad, round eye, be- 

 hind which is a cavity, in vhirh is placed a small, moveable body, furnished with minute spines. At 

 the anterior edge, near the base of the beak, are situated the pieces which have been considered as the 

 antenna', which are scarcely so long as the head, and are composed of four nearly cylindrical joints. 

 The slieatli of the beak is composed of three joints. The abdoraen is very large, and each of its seg- 

 ments is divided in two, being formed of two plates, one superior and the other inferior. The legs are 

 robust, particularly the posterior, fitted for leaping, spinose, with the coxas and thighs very large, and 

 the tarsi composed ef five joints, the Pist terminated by tHO lung nails. The two fore-legs are ijiserted 

 almost beneath the head, and the beak is placeil between them. 



The female lays about a dozen white, slightly viscid eggs, whence emerge small Iarva>, destitute of 

 legs, very nuich elongated, resembling minute worms, very active, coiling themselves up in a circle or 

 spire, scrpenting in tlieir progress, at first white and afterwards reddish. Their body is composed of a 

 scaly head, without eyes, bearing two very minute antenna; and thirteen segments, with small tufts of 

 hairs and a pair of little liooks at the tip of the last. The mouth exhibits a few smaU, moveable parts, 

 of wliich the larva; make use in pushing themselves forwards. After living about twelve days under 

 this form, these larvi-e inclose themselves in a small silken cocoon, where they become pupse, and from 

 whence they make their escape in the perfect state, at the expiration of a similar period. 



I ] Everyone knows tlie coinmnn Flea (Piilex irritans, Linn.), wliich 



feeds on the blood of Man, the Dog, and Cat. Its larv'a lives aniongfst 

 dirt, and beneath the nails of hithy persons ; also in the nests of birds, 

 such as Pi£:eons, attaching itself to the necks of the young, and gorging 

 itself till it becomes red. M'ell tiijured byDameril (Comid. Gt'tierafes 

 sur la ijlasse dca Insccte.'!.) — Pidex pencti-ans, Linn., probably forms a 

 peculiar genus. Its beak is of the length of the body. It is known in 

 America under the name of the Chigoe [or Jigger]. It introduces itself 

 beneath the nails of the feet and the skin of the heel, where it soon ac- 

 quires the size of a small pea, by the quick growth of the ec'gs, which 

 it bears in a large membranous bag beneath the abdomen, the nume- 

 rous family from which occasions, by remaining in the wound, an 

 ulcer, very dilTicult to heal, which even sometimes becomes mortal. Frequent washings, and rubbing the feet 

 with fresh tobacco leaves, or those of other bitter plants, are preventives against its attacks. The negroes [or 

 moi-e commonly the upgresses] are in the biiliit of extracting the insect, with great skill, from its lodgement. 

 Various (piadiiipfils aiiil liii-ds nonii:^h Fleas, which appear to ditler specifically from the two preceding. 



[The structur(^ of the lieail and mouth of these insects has been investigated by i-ecent cntonio- 

 logi-ts, es])ecialh- hv Curtis, Diiges, and myself. Tlie moveable organs noticed ahovc, implanted in a 

 cavity at the hack of the sides of the head, arc proved to be antenna", varying considerably in form in 

 various species. Their \ariafions have led to the proposal of another genus hir certain s]a"cics, by 

 Jlr. Curtis. The i«o flat pieces noticed by Rccsel, are the lancet-like mandibles ; the two conical scales 



at the base of tlir I ili are the maxilLT, the long antenna-like organs in front of the head being the 



maxillary palpi ; tlie third piece, noticed above as described by Kirby, is the slender setifonn tongue, 

 and the two articiilatcil plates above described are the labial palpi, arising from a common labium. 

 Thus the mouth is seen to consist of all the essential parts, except an upper lip, which is obsolete in 

 many other tribes. M. Duges has also detected two scales on each side of the meso- and mctatliorax, 

 which he considers as the real analogues of the two pairs of wings. 



Various species of Fleas have been described by Curtis, Duges, &c. Tlie Chigoe has also been in- 

 visligated hy Duges, Guerin, and myself, from whence it appears that the large mass of eggs causes 

 the ahilonicu to become immensely swollen. The mouth is of the ordinary t\]ie, hut the loiver lip is 

 destitute of labial ])al]ii, whence I have ]iro]iosed for it the generic name of S'arcnji.yi/lh's, or Fle^h-tlca.] 



