324 ARACHNIDES. 



Huntsmen in France call the species which attaches itself to the 

 Dog, Louvette. It is the 



Ixodes ricinus; Acarus ricinus, L.; Acarus reduvius, DeGeer, 

 Insect., VII, vi, 1, 2. A deep blood-red; the sealy, anterior 

 plate still darker; sides of the body turned up, and slightly 

 hairy ; palpi forming a sheath to the sucker. 



Ixodes reticulatus, Lat. Fab.; Acarus reduvius, Schrank, 

 Enum. Insect,, Aust., No. 1043, iii, 1,2: Cynorhcestes pictus, 

 Herm. Cinerous, 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 six 

 lines in length. 

 The species of this genus have not been sufficiently studied *. 



Arg-a.s, Lat. — Rhynchoprion, Herm. 



Distinguished from Ixodes by the inferior situation of the mouth, 

 and by the palpi which do not encase the sucker, have a conical 

 form, and are composed of four joints, and not of three, as in the 

 preceding genus. 



Argas rejlexus ; Ixodes rejlexus. Fab, ; Lat. Gen. Crust, et 

 Insect., I, vi, 3, Herm. Mem. Apt. IV, 10, 11. Pale yellow, 

 with dark blood-coloured, or obscure and anastomosing lines, — 

 On Pigeons. 



Argas persicus ; Malteh de Mianeh. This species, described 

 by travellers under the name of Punaise venimeuse de Miana, 

 with other Ixodes, constitutes the subject of some curious obser- 

 vations published by M. Gotthef Fischer de Waldheim. 



Others again — Hydrachnell^, Lat. — have also eight legs, but 

 they are ciliated and adapted to natation. 



They form the Genus Hydrachna of Miillerf or ihdii oi Athax 

 Fab., and are wholly aquatic. Their body is generally oval or nearly 

 globular, and very soft. That of some males is narrowed posteriorly, 

 so as to resemble a kind of tail, their genital organs being 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, accord- 

 ing to Miiller, 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 

 Miiller's species of Hydrachnse, that naturalist not having described 

 them with sufficient minuteness. 



* Acarus agyptius, L. ; Herm. Mem. Apter., IV, 9; L. IV, 13; — Acartts rhino- 

 cerotis, De Geer, Insect., VII, xxxviii, 5. 6; — Acarus americanus, L. ; — Ac. nigua, 

 De Geer, lb., XXVII, 9, 13. See the genus Ixodes of Fabricius, and the work of 

 Leach on the apterous Insects of Linnaeus — Trans. Lin. Soc, XI. 



f Hydrachna, Herm. 



