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Show 260 INSECTA. Quadrupeds. That which lives on the Hog has a very narrow tho. rax with a very wide abdomen, and forms the genus Ht:ematopinU8, Leach( 1 ), the Pou du Bu.flle, figured by De Geer, I!lsect., VII, 1, 12, presents more important characters. The others-Nirmidia, Leach-such as the RiciNUS, De Geer-Nirmus, Herm. Leach, Have the mouth infet·ior, and composed externally of two lips and two mandibles, resembling hooks. Their tarsi are very distinct, articulated, and terminated by t.wo equal hooks. One single species excepted, that of the Dog, they are all exclu. sively confined to Birds. Their head is usually large, sometimes tri· angular, and at othet's forming a semi-circle or crescent, and fre. quently presenting angular projections. It sometimes diffet·s, like the antennce, in the two sexes. I have perceived, in several, two sim. pie approximated eyes on each side of the head. According to the observations of M. Savigny, communicated to me by himself, these animals are provided with jaws, each of which has a very small palpus, hidden br the lower lip, which has also two organs of the same desr.ription. They have moreover a kind of tongue. M. Leclerc de Laval informs me that he has found parcels offea. thers in their stomach-he thinks that they constitute their only food. De Geet·, however, assures us that he has found the Pediculus of the Fringilla ccclebs filled with recently imbibed blood. It is well known that these Insects survive but a short time on dead Birds. When thus situated, they are observed to wandet· over their plumes with much anxiety, those of the head and the vicinity of the beak espe· cially. Redi bas also represented a great number of species of this sub· genus. The mouth of some is situated near the anterior extremity of the head. The antennce are vet·y small, inserted laterally, and at a dis· tance from the eyes(2). In the others, the mouth is nearly central; the antennre are placed close to the eyes, and their length about equals half that of the head(3) (1) Zool. Miscell., CXLVI; P. suis, Panz.,' Faun. Insect. Germ. LI, xvi,l. The P. cervi, Panz., lb., xv, belongs to the genus Meloplwgus, of the Dip· tera. (2) Pediculus sternre ldrundinis, L.; De Geer, Insect., VII, iv, 12:-Ped. co1-ri coracis, I..; De Gcer, Jb., ii;-Ricinus fringil!UJ, De Geer; lb., 5, 6, 7;-Ped. tin· nunculi, Pnnz., lb., xvii. (3) Ricinus gallinre, De Geer, lb ., 15-on the Cock, Partridge, and Pheasnnt;- 261 The celebrated pt·ofessot· Nitzsch has profoundly studied the in- 1 as well as external ot·ganization of these animals, as may be terna . . . . . n by referring to lus paper on the Ep1zo1c Insects, m the Magasm dseeer Entornologic of M. Germar. 'I'h e genus p e d"t culus, properly so called, 01• that whose species are provided with a sucker, is arranged b him with the Epizoic Heri1iptcra. The Ricini of De Geer and o;hers, or the Nirmi of Hermann, Jun., that is to say, the species furnished with mandibles and jaws, arc referred to the Orthoptera, and collectively designated. by the tet·m Mallophaga. Two genera of this division npproach the preceding ones in the cit'cumstance of living on the Mammalia-such arc TRICllODEOTEs and Gvnopus. In the first the maxillat·y palpi arc null or indistinct, and the antennre filiform, and composed of three joints. The species of this genus are found on the Dog, Badger, &c. In the second the maxillary palpi are appat·ent, and the antenncc, thicket· towards the end, consist of four joints. The mandibles have no teeth; there are no labial palpi, and the four postel'ior tarsi hare but a single terminal hook. These last chat·acters distinguish it from another genus, also furnished with visible maxillary palpi, quadriarticulated antennce thicker near the extremity, and an anterior mouth, that of LIOTHEUM. Here the mandibles are bidentate, the labial palpi distinct, and all the tarsi terminated by two hooks. The species are found on various Birds, whereas the Gyropi live on the Guinea-pig. A fourth and last genus, the species of which are exclusively confined to Birds, is that of PmtoPTEnus. The antennce consist of five joints, the third of which, in the male, frequently presents a branch that forms a forceps with the first; these organs are filiform. The maxillary palpi are invisible. The tarsi have two hooks at their extremity, but they do not diverge like those of the Liothea. Besides this, the males here have six testes, three on each side, and their four biliary vessels are thickened near the middle of their length. Those of the Trichodectes and Philopteri do not exhibit this enlargement, and they have but four testes, two on each side. In these two genera there are also ten ovaries, five on each side; in such of the female Liothea as this savant could find them, he saw but six, three on each side. He has no positive knowledge of the number of those in the female Gyropi, nor of that of the testes in the males. In all these genera the thorax is bipartite, that is, the prothorax and the mesothorax compose the apparent trunk, and the thi1·d division, or the R. emberizre, De Gce1·, lb., 9;-R. mergi, De Geer, lb., 13, 14;-R. canis, De Geer, lb., 16;-Pediculus pavonis, Panz., lb •• xix; Lat., llist. Nat. des Fourm., 389,xii, 5. Sec also Panz., lb., pl. xx-xxiv. His Pediculus arde<e, XVIII, ap· pears to be the same as the Ricin du p/ongeon, De Geer, IV, 13. |