ORDER ACARINA : THE TICKS 275 



_ /Stigmata comma-shaped ; anal groove present = Rhipicephalus. 



\Stigmata oval or circular ; no anal groove = 8. 



rXwo pairs of adanal plates in male ; legs normal Boophilus. 



8. -: One pair of fused adanal plates in male ; segments of legs remark- 



(_ ably expanded, particularly in male Margaropus. 



Ixodes, Latreille (l^wSri^^a. sticker). The anal groove 

 arching in front of the anus is characteristic. The 

 rostrum is moderately long ; the hind edge of the body is 

 not festooned ; there are no eyes ; and in the male the 

 whole, or the greater part, of the venter is covered by 

 chitinous plates. Neumann recognises forty-six valid species, 

 distributed in every part of the world. Perhaps the 

 commonest and most notorious species is Ixodes ricinus, 

 which is found in Europe, Asia, North Africa, and North 

 America, and among its numerous hosts includes all the 

 common domestic animals, and occasionally man. Neumann 

 separates as distinct subgenera two species, in which the 

 pedipalps of the male are cylindrical in section ; one of these 

 {Eschatocephalus), found on various bats in the Palasarctic 

 Region, has the pedipalps spatulate ; the other {Ceratixodes), 

 found on aquatic birds in Polar seas has the pedipalps acute. 

 Aponomma, Neumann (ctTroi'o? = untroubled with ; o)j.{xa 

 = eye). The body is subcircular, at least in the male, 

 and the scutum often is spotted in green or golden yellow. 

 Neumann admits eleven species, distributed in Africa and the 

 Oriental and Australian regions, and parasitic almost 

 exclusively on reptiles. 



Amblyomma, Koch (ay«/3\iJ? = weak ; o/ufia^eye). The 

 body is rather broadly oval, and often there are lustrous metallic 

 markings on the scutum. According to Neumann there 

 are seventy-three valid species at present known, distributed 

 in the Ethiopian, Oriental, Australian, and Neotropical regions 

 (see p. 7). Though they very rarely attack birds, they are 

 parasitic on all other kinds of land vertebrates. 



Hyalomma, Koch (i/aXo? = clear ; ofji,iJ.a = eye). Males 

 of this genus are easily distinguished from males of 

 Amblyomma by the presence of adanal plates. Females can 

 generally be distinguished from those of Amblyomma by the 

 more elongate-oval body and by the comma-shaped stigmata. 

 Neumann accepts four species, widely distributed in South 



