Experimental attempts to transmit heartwater (Rickettsia 

 ruminantium) of cattle through this species have failed. 



REMARKS 



A, marmoreum is considered by most workers to parasitize 

 chiefTy the rhinoceros and tortoise but Theiler (correspondence) 

 has fovind so much variation in morphology and host data on spec- 

 imens sent from various parts of Africa that she prefers to refer 

 to «n specimens as '"A. marmoreum group'" until they can receive 

 more intensive study." Most of her specimens come from tortoises, 

 a few from Varanus lizards and cattle. She considers the rhino- 

 ceros to be an accidental host, or else the host of a separate, 

 as yet unrecognized, species or subspecies. She has large num- 

 bers of nymphs of this group from fowls. 



Schulze (1932a) realized the complexity of the marmoreum group 

 and proposed new names for specimens from various parts of Africa. 

 Reasons for these differentiations appear quite invalid. 



A definitive species name for Sudan material awaits assign- 

 ment. The range of variation in even the rather small series of 

 Sudan specimens at hand casts considerable doubt on the validity 

 of all those '"related species'* that are based on certain aspects 

 of scutal ornamentation or on coxal spur characters. 



The structure of the larval eye and its sense organs in spec- 

 imens of the A. marmoreum group has been described and illustrated 

 by Gossel (1935). 



Nuttall (l9LiA) reported on a malformed specimen of A. mar- 

 moreum , from the Siidan, and Schulze (l9Al) noted characteri st ic s 

 of the haller's organ of this species. 



IDENTIFICATION 



Males ; Large, at least 6.0 mm. x 5-0 mm. Scutum with 

 reddish-yellow ornamentation that is variable but essentially 

 as illustrated; pale areas in this species are more separated 



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