414 



CRUSTACEOLOGY. 



11. BDEL- 

 LA. - 



Rubra. 



12. Sma- 



RIS. 



Sambuci. 



13. Chey- 



LETUS. 



Eruditus. 



14. Uropo 



laces et des Insecles, torn. 7. pi. 66. fig. 8. under the 

 name sarcopte de la gale. 



Obs. To this genus the following species seem to be- 

 long, Acarus exulcerans, Linne ; Acarus destructor of 

 Schrank, (Eiwmeratio Insectorum Austria;, No. 1057.) 

 and Acarus torosus of Hermann. 

 B. Palpi apparent. 



Genus XI. Bdella. Lair. Lam. Acarus. Linn. 

 Fabr. Scirus. Her. 



Palpi elongate and generally geniculated, the last 

 joint with two distinct long setae or hairs. 



Mouth with an elongate, depressed, conic rostrum ; 

 defended by three valves, or nearly equal lanceolate 

 seta?. 



Body ovate, transversely divided into two parts. 

 Eyes four. 



Feet posterior, longer than the rest. 



Sp. 1. Rubra. Antennae geniculated, the second and 

 third joints very short ; the first and last elongate ; ros- 

 trum longer than the thorax, subulated ; body blood 

 red ; feet pale. 



Bdella rubra, Lamarck. 



Acaris longicornis, Linn. ? 



Inhabits Europe, under stones. 



Observe. Scirtts longirostris of Hermann, appears 

 to be not very distinct from the above species ; p. 62. 

 tab. 6. fig. 12. He mentions two other species, viz. 

 Latiroslris, and Setirostris ; the first is distinguished 

 by its rostrum being shorter than the thorax ; the an- 

 tennae three-jointed, the last joint shortest: the second, 

 by its subulate rostrum, antennae with two joints, the 

 apex with one seta. They both inhabit mosses, and 

 are of a red colour. 



Genus XII. Smaris. Latr. Acarus Schrank. TroM- 

 bidium, Hermann. 



Mouth with an elongate, somewhat cylindrical por- 

 rected rostrum, with the apex gradually becoming 

 narrower. 



Palpi nearly parallel, straight, subcylindrical, and 

 porrected, consisting of four joints, the last with no 

 elongate setae ; they are a little longer than the ros- 

 trum. 



Body oval and scaly. 



Eyes two. 



Feet, anterior ones longer ; the four hinder distant. 



Sp. 1. Sambuci. Body red. 



Acarus sambuci. Schrank. 



Trombidium sambuci, Hermann. 



Sm a ris sambuci, Latr. 



Inhabits trees, especially the elder. 



Genus XIII. Cheyletus. Lair. Acarus, SchranJc, 



Palpi very thick, resembling arms. 



Sp. 1. Eruditus. Body brownish. 



Acarus eruditus, Schrank. 



Cheyletus eruditus, Latr. 



Inhabits books and musaea. 



II. Eyes indistinct. BonY with a covering, partly 

 membranaceous, partly coriaceous. The haustellum 

 with three horny laminae toothed on the side ; (these 

 animals suck the blood of mammalia, birds, and rep- 

 tiles.) 



A. Rostrum and palpi obscure. 



Genus XIV. Uropoda, Latr. Acarus, De Geer, 

 Donovan, Sc/iaw. 



Feel very short (when at rest pressed and contracted 

 against the under part of the body), the fourth long- 

 est, then the third ; the first very short, received into 

 a cavity on the anterior part of the body beneath. 



Body oval, inclining to orbicular ; back horny and 



shield-formed, the middle gradually convex ; the un- 

 der part smooth. The anus fixed to coleopterous in- 

 sects by a long filiform peduncle. 



Sp. 1. Vegetans. Body brown, very smooth and Vegetans 

 shining. 



Acarus vegitans, De Geer, Shaw. 

 Acarus coleoptratorum, jun. Donovan. 



Uropoda vcgilans, Latreille. 



Inhabits sphaeridea, histeres, scarabaei, and apho- 

 dii. 



This curious animal is found on most of the dung- 

 feeding coleopterous insects. Donovan has figured this 

 species for the young of Gamasus coleoptratorum. 

 B. Rostrum and palpi distinct. 

 Genus XV. Argas, Latr. Rhynchoprion, Herman, is. A*caa. 

 Acarus, Fabr. 



Palpi conic, short, incurved, consisting of four joints. 

 Body oval, membranaceous, the skin not more corea- 

 ceous before than behind. 



Feet arising from nearly the middle of the vertex, 

 with two nails at their extremities, inserted and elon- 

 gated, the joints rounded at their base. 



Sp. 1. Refiexus. Pale yellowish, or flesh-coloured RefleiuS. 

 inclined to violet; body marginated, the squamulae 

 very short, the sanguiferous vessels branched. 



Acarus marginatus, Fabr. Coquebert. 



Argas refiexus, Latr. 



Inhabits houses, sucking the blood of pigeons. 



Observe. Latreille thinks it highly probable that 

 Acarus niger of De Geer, (torn. 7- pi- 37. fig. 9.), and 

 Rhyncoprion americanum of Hermann, (p. 71.) form an 

 intermediate genus between Argas and the following 

 genus Erodes. Should this be found correct, it might 

 be named Rhychoprion, which would prevent any use- 

 less confusion arising from synonyms. 



Genus XVI. Ixodes, Lair. Acarus, Lin. Fab. Oliv. 16. 'xoo.t 

 Cynorhestes, Herm. 



Palpi terminal, porrect, very short, coriaceous, plain, 

 depressed, longer than broad, nearly of an equal breadth, 

 the apex rounded or obtuse, inserted at the base of the 

 haustellum on a common peduncle, sheathing the haus- 

 tellum and rostrum. 



Rostrum oblong-quadrate, depressed, obtuse, three- 

 pointed ; the basilar joint very small ; the others nearly 

 equal ; the internal edge hollow. 



Haustellum horny, with three lamellae. 



Body ovate-orbicular, membranaceous before, and 

 notched for the insertion of the rostrum ; the anterior 

 part of the back coriaceous, somewhat resembling a 

 thorax. 



Feet inserted at the lateral margins, the joints thick; 

 the last, with two nails, inserted on a vesicle ; the ve- 

 sicle pedunculated. 



Sp. 1. Ricinus. The rostrum, thoracic mark on the Ricim* 

 dorsum, and feet blackish red ; the abdomen light red, 

 with a few scattered villi, the sides marginatis ; the 

 palpi free, or scarcely sheathing the haustellum. 



Acarus ricinus, Linn. Fabr. 



Ixodes ricinus, Latr. 



Inhabits the woods and groves of Europe, attaching 

 itself to oxen and dogs, and adhering firmly by their 

 rostrum and feet. Is very common in Britain ; is known 

 by the names tick, or dog-tick, or tique. 



Sp. 2. Sanguineus. Blood red, and punctated or Sangm- 

 dotted, with three impressed lines behind ; the dorsum neus ' 

 without any distinct mark on the anterior part. 



Inhabits France, and is here given on the authority 

 of that celebrated entomologist Latreille, who says it 

 is rather smaller than the preceding species. 



