Integvimentary sense organs, which are fixed in number and 

 location and essentially similar in all stages, though more 

 primitive in larvae, have been described and illustrated by Dinnik 

 and Zumpt (19A.9) . These are the organs that Delpy (1938) had 

 previously referred to as spiracles ("stigmates respiratoires"). 



Pervomaisky (19A9) was unable to rear a full Fi generation 

 from parthenogenetic females of H. dromedarii . Abnormal specimens 

 have been described by Pavlov sky"~(l9A-0; and Alfeev (19/+8). 



The feeding of large numbers of this tick (r H. asiaticum ) 

 induces inflammation of the host skin that hinders"normal engorge- 

 ment, especially of females that are likely to die as a result. 

 When additional species compete for space, "a further antagonistic 

 factor increases the obstacles" (Pavlovsky, Pervomaisky, and 

 Chagin 195^). 



Warburton and Nuttall (1909, page 7l) produced an excellent 

 illvistration of H. dromedarii (H. aegyptium ) but the legend, 

 inferring South Xfrica as the source, is misleading. Apparently 

 the only specimen from South Africa is the abnormal one (figure 

 18), the identity of which is uncertain. 



"H. asiaticum " , which Delpy considers to be a synonym of 

 H. dromedarii , is still treated by Soviet workers (Pomerantzev 

 T95OJ as a separate species with several subspecies and with a 

 wider geographical range than H. dromedarii . This form is less 

 robust, smaller, and more slen'Ser, with a shorter posteromedian 

 groove than in giant males typical of H. dromedarii . The fe^ 

 males are more elongate than the typically robust female H. 

 dromedarii and the length- width ratio of their palpi and of 

 their scutttm is longer. Such individuals are also encountered 

 in African populations. Delpy (19A6) first considered the short, 

 wide palpal shape to be diagnostic but further studies indicated 

 so much variation that "applied strictly to determination of 

 isolated specimens, (this character) would have led to errors. 

 (Also) the ratios that are true for a young, recently molted 

 tick are no longer accurate when this tick has aged and become 

 engorged". The shortness of the posteromedian groove appears 

 concomitant id.th the general lack of robustness in these smaller 

 and more slender ticks. 



- 431 - 



