significance of iKjrphological variations such as the lightly puna, 

 tafe forms from Equatoria Province birds in an area where most of 

 those parasitiziS mammals ^e heavily P-fate? ^^l^^^flf^lf 

 strains" or varieties exist in Africa and do some or all of these 

 react with equal facility to domestication? What is the life 

 cycle under field conditions and what are the host predilections 

 of the immature and adult stages away from human and domestic 

 canine habitations? Why does parasitism of persons - aM bou- 

 tonneuse fever - appear to be so much more common in north, 

 western Africa thl^^TSewhere on this continent (and why is 

 boS^^e^e fever absent in Egypt)? J-t what is there about 

 a habitation shared by man and dogs, whether -t be an African 

 hut or a Florida mansion, that is so much more attractive to 

 ?Ss tick than a fox den in a rocky hillside? Is the greater 

 incidence of parasitism of all domestic norucanme animals in 

 Se Near East, as compared with tropical Africa merely a matter 

 o? hosravaiUbility?' These are but a few of the innumerable 

 inquiries that suggest themselves as a result of our lack of 

 specific information concerning this common tick. 



Life Cycle 



The life cycle of R. s. sanguineus has been studied, under 

 laboratory conditions, -By T^h risiSphers (19QX), Hooker, Bishopp, 

 ^fwood a912)S Patron and Cragg (1913) with techniques i^ 

 Sttra?ed Nutiail (1915), and ^egendanz and Keichenow (l93l) . 

 In the discussion below, less specialized life cycle reports 

 S stiiies for special purposes are noted following the suiiu 

 mary of the above-mentioned papers. 



All observers agree that this is a three-host tick. Varia. 

 tion in reports of Sngth of feeding time of each stage may be 

 die to the kind of host used in laboratory experiments (see 

 tSlow). During nonfeeding phases temperature and humidity 

 exert considerable influence on the length of the 1^^^^^^^^'^^ 

 Nuttall concluded that feeding times are ^°"^^^^' J^^f ^^"3^^ 

 of temperature variations, and that only the nonfeeding phases 

 are affected by these variables (see also discussion of this 

 aspect under H. dromedarii , p. U2.S) . 



^he extensive data in this important paper are not reviewed here. 



- 70/. - 



