organ with that of other Ixodes species is presented in table form 

 by Arthur (1956B). 



Remarks on morphology of this species are contained in papers 

 by K. W. Neumann. These have not yet been seen and complete ref- 

 erences are not available except for: (19^2) Z. Morph. ftkol. Tiere, 

 38(2) ;358, 362. (Morphology of subcoxa of subspecies cumulatim - 

 lunctatus ); and (l9i!k5) Zool. Jb. (Anat.), 69(2): 286, fig. 8. Jakob 

 T552[B7~Tncluded this species in his review of the relationship of 

 tick genera from the standpoint of comparative morphology. 



f 



Both sexes are readily distinguished by their completely closed, 

 usually circular anal grooves, an easily observed character in all 

 specimens except some greatly engorged females in which the anal 

 area is depressed and the associated grooves are difficult to dis- 

 cern. Only one other African species, Ixodes ugandanus Neumann, 

 1906 (with which Ixodes ampullae eus Warbxirton, 1933, from Uganda 

 is quite possibly synonymous J, is known to have closed anal grooves; 

 these are not circular but characteristically oval and \mite in a 

 slight posterior elongation, I. ugandanus has not yet been found 

 in the Sudan. ~ 



Schulze (1943A) indicated that circular anal grooves are char- 

 acteristic of this species but that some specimens in which these 

 grooves are expanded to a broad oval outline are merely atypical 

 individuals of the same species. According to Schulze, the ansuL 

 grooves of I. rasus may even be narrowed posteriorly. 



Schulze (19A3A) differentiated three subspecies of I. rasus 

 and one "related species" as follows: " 



I. rasus rasus ; Short, broad palpi and hypostome; retro- 

 grade""atiriculae (lateral spurs of ventral basis capitiili); pro- 

 nounced single punctations on scutum. (From Cameroons). 



1. rasus cvimulatlmpunc tatus : Long, narrow palpi and hypo- 

 stome" perpendicular auric\xlae; and small scutal punctations, 

 some of which appear to be formed of a small group of smaller, 

 contiguous punctations. (Tanganyika to Fernando Po). 



1. rasus eidmanni ; The sajne characters as given above for 

 I. ra'sus rasus , but "more strongly chitinized and darker", and 



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