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Show 218 ARACIINIDES. Sometimes these Ticks, with eight legs and without chelicerl! have no eyes that are perceptible; their pal pi are either anterior an~ projecting, but in the form of valvulce, widened or dilated near the extt·emity, se1·ving as a sheath to the sucker-or inferior; the parts composing the sucker are horny, very hard and dentated; the body is invested with a coriaceous skin, or has at least, anteriorly, a scalr plate. These animals are parasitical, gorge themselves with the blood of seve1·al of the Vertebrata, and from being extremely fiat, acquire by suction a great volume and a vesicular form. They are roundor oval. IxoDEs, Lat. Fab.-Cynorh::eates, Herm. The palpi forming a sheath to the sucker, and with it constituting a projecting and short rostrum, truncated and slightly dilated at the extremity. The Ixode~ are foulld in thick woods abounding in brushes, briars, 8tc.; they hook themselves to low plants by the hind legs, keeping the others extended, and fasten on Dogs, Oxen, Horses and other Quadrupeds, and even on the Tortoise, burying their sucker so CO!i1· pletely in their flesh, that they can only be detached by force, and bJ tearing out the portion that ad heres to it. They lay a prodigious quantity of eggs, which, according to M. Chabrier, are protruded from their mouth. They sometimes increase to such an enormous extent on the Ox and Horse, that they perish from the exhaustion. Their tarsi are terminated by two hooks inserted in a palette, or united at base on a common pedicle. The ancients designated these Arachnides by the term Ricinu6. Huntsmen in FL"ance call the species which attaches itself to the Dog, Louvette. It is the Ixodes ricinus; .IJ.carus ricinus, L.; .Jlcarus reduvius, De Geer, Insect., VII, vi, I, 2. A deep blood-red; the scaly, anterior plate still da1·ker; sides of the body turned up, and slightly hairy; palpi forming a sheath to the sucker. Ixodes reticulatus, Lat. Fab.; .IJ.carus reduvius, Schrank, Enum. Insect., Aust., No. 1043, iii, I, 2: Cynorha3stes pictu!, Herm. Cinereous, with small reddish-brown spots, and little annular lines of the same colour; edges of the abdomen striate; palpi nearly oval. It infests Oxen, and when tumefied, is sii lines in length. The species of this genus have not been sufficiently studied{!). ---------------------------------------------- --- ( 1) .9.caT'U8 te.gyptiua, L.; Herm. Mem. Apter., IV, 9; L. IV, 13 ;-.Bcaruu~in~ eeroti&, De Geer, Insect., VII, xxxviii, 5, 6;-AcartU americanua, L.;-.Bc. nrgu4. TRACliEARilE. 219 ARGAs, Lat.-RHYNOHOPRioN, He1·m. Distinguished from Ixodes by the inferior situation of tbe mo~th, db the palpi which do not encase the sucker, have a comcal 10 y d are composed of four joints, and not of three, as in the form, an receding genus. p Jlrgas reftexus; Ixodes reflexus, Fab.; Lat. Gen. Crust. et In-sec t ., I , vi ' 3 ' Herro. Mem. Apt. IV, 10, 11. Pale yellow, with dark blood-coloured, or obscure and anastomosing lines.-On Pigeons. . . . . .!lrgas persicus; Malleh de Mtaneh. This species, descr1bed by travellers under the name of Punaise venimeuse de Miana, with other Ixodes, constitutes the subject of some curious observations published by l.YI. Gotthef Fischer de Waldheim. Others again-H YDRAOHNELLJE, Lat.-have also eight legs, but they are ciliated and adapted to natation. They form the Genus H YDRAOHNA of MUller( 1) or that of .IJ.thax Fab., and are wholly aquatic. Their body is generally oval or nearly globular, and very soft. That. of so~e ma~es is narrowe~ posteriorly, so as to resemble a kind of ta1l, thell' gem tal organs bemg placed at its extremity; in the female, they are on the inferior surface of the abdomen. The number of eyes varies from two to four, or, according to Mi.iller, even to six. The mouth of those species, I have been able to study, offered the three following modifications, which have served as a base to three generic divisions, but to which it is almost impossible to refer all MUller's species of Hydrachn::e, that naturalist uot having described them with sufficient minuteness. EYLArs, Lat. Chelicer~ terminated by a movable hook(2). H YDRAOHNA, Lat. The mouth composed of lamince, forming a projecting sucker; a movable appendage under the extremity of the palpi(3). De Geer, lb., XXVH, 9, 13. See the genus Ixodes of Fabricius, and the work of Leachon theapterous Insects ofLinnreus-Trans. Lin. Soc., XI. (1) Hydrachna, Herro. (2) .llta:t eztendena, Fab.; MUll., IX, 4. (3) .IJ.tax geographicw, Fab.; Mull., Vlll, 3, 5;-.R.t. globator, Fab. 1 MUll., IX, 1. |
