Animals of the Tkansvaal Museum. 



93 



Tlie name Lvodes lias served to describe the greater part of the 

 Ixodinac of various countries and hosts. Although Koch gave a 

 restrictive diagnosis, yet the inexperienced authors continued to 

 include the nio.st varied forms in this genus ; most of the descriptions 

 were incomplete, insuthcient, and their identification usually 

 impossible. Koch himself has added to the confusion by giving the 

 rank of species to forms, which differ only in age, or stage of 

 engorgement, shape or size, secondary ])oints in a question of this 

 sort. 



The genus is sub-divided into three sub-genera — Euixodes, 

 Ceratid'odes and EsrhatorepJial ifs . These were formerly considered as 

 three distinct genera, but ^N^eumann considers that the characters 

 which distinguished Cerafi.vodes and EscJtafocepJudus from Ixodes 

 were not of sufficient importance to justify this distinction, therefore 

 he included them in the genus I.vodex. 



The three su])-genera are characterised as follow: — 



Eui.rodc^. Pal})i long, valvate ; no eyes, anal groove may be 

 open or closed behind ; in the male one pregenital, one genito-anal, 

 two epimeral, one anal, and two adanal plates; stigmatic plates oval 

 in male, circular in females. 



Ceratid'odes. Palpi long, convex inside, and with a conical pro- 

 longation in the male, and swollen at the end in the female. No 

 eyes. Anal groove absent in female, but present in male. One anal 

 and two adanal shields in the male; stigmatic plates circular in both 

 sexes. 



EscJiatocepJiahis. Palpi long, claviform, and flat in the female, 

 piriform and not valvate in the male ; anal groove contouring anus 

 in front and open behind. Stigmatic plates circular in both sexes. 

 Irregular chitinous thickenings both above and below in the nmle. 

 Stigmatic plates circular in both sexes. 



So far only three forms of Erodes are known in South Africa. 

 Lvodes pilosus occurs in the Cape Colony and Orange River Colony, 

 while its variety, Ixodes pilosus hoicordi, is found in the Transvaal 

 and jNTatal. Lvodes ruhieundus is reported and described by Neumann 

 from specimens taken in Cape Colony. 



Males. 



A. Anal shield horseshoe shaped. 



B. Male large, 3.15 mm. long by l.G mm. wide; teeth on 

 hypostome in one marginal row, other rows represented 

 by crenulations ... ... ... ... ... pilosus. 



BB. Male small, 2.3 mm. long by 1.2 mm. wide ; teeth on 

 hypostome in three or four rovrs ... pilosus Jiowardi. 



AA. Anal shield rectangular; sides parallel, longer than wide. 



ruhieundus . 



