Feldman-M'uhsam 194-8 in Palestine; Brumpt and Chabaud 1947 in 

 France, and Serdynkova 1946A in Russia) confirm that this is 

 normally a three-host species. In Tadzhikistan, however, Lotot- 

 sky and Pokrovsky (1946) consider H. excavatum (= H. anatolicum ) 

 to be a two-host tick. Feldman-MuEsam observed th'at some larvae 

 may remain on the host through the nymphal stage, but Delpy 

 (1946c) stated that if they do so, they first detach and wander 

 away, for example to the ear, and reattach only after molting. 

 Daubney and Said observed a single larva molting while still 

 attached. On desert rodents in Egypt nymphal H. excavatum have 

 on several occasions been foxind attached to the host and par- 

 tially enclosed by the laarval exuvia. Possibly in these situa- 

 tions, where hosts are scarce, the typical life cycle is more 

 commonly somewhat altered. On Egyptian deserts, the molt from 

 nymphal to adult stage typically occvirs in rodent burrows. 

 Remarks that desert rodents dislodge most ticks attached to them 

 by rubbing, shaking, or eating are cpntrary to frequent experience 

 in Egypt. 



The effect of a small size host on the life cycle of H. 

 excavatum has perhaps best been described by Serdyukova (i946A, 

 as H. aniatolicvmi ) (from abstract in Review of Applied Entomology): 



"Larvae from a single egg-batch engorged on a 

 rabbit, which is an unusual host for this tick. Some 

 detached after engorgement, others molted on the ani- 

 mal. Some of the resulting nymphs wandered on the 

 rabbit without feeding but others engorged and then 

 dropped off. Larvae placed on the ears of a calf all 

 detached after engorging, and no engorged or molting 

 larvae or larval exuvia were observed on csLLves in 

 the field. Ticks collected in a calf shed included 

 freshly engorged and molting larvae and unfed nymphs. 

 It is concluded, therefore, that H. excavatum (= H. 

 anatolicum ) develops as a threeuhost tick on its " 

 normal host, but that an unusual host may alter this 

 behavior. The cycle of ixodid development has probu 

 ably altered as a result of evolutionary processes. 

 The typ)e of development that occiirs on the usual 

 host shoxild be considered as normal, and deviations 

 from it on unusual hosts as atavistic." 



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