place during the winter nymphs molt and adults feed. In Egypt, 

 wild nymphs do not normally molt imtil almost summertime, pos- 

 sibly because of cold nights during early spring. By late March, 

 however, females begin to feed, and at this time they may oviposit 

 very shortly after dropping from the host _ as soon as seven days 

 afterwards. The incubation period may be as short as 27 days, so 

 that in May new larvae and last year's nymphs can be found feeding. 

 Under the Russian conditions already mentioned, oviposition does 

 not commence until Jiily or August and it appears that there is 

 only a single generation a year in those climes. In Tadzhikistan 

 (Lototsky and Pokrovsky 194-6), adxilts of H. excavatinn (= H. 

 anatolicum ) infest cattle from the end of""February to November, 

 and larvae and nymphs from July through September; all stages 

 are most numerous early in August. 



Larvae feed for from four to six days (320C., 1% R.H.) 

 according to Feldman-Muhsam, but the Russian observer reported 

 only two to four days in nature. Larvae molted six days after 

 leaving the host (30°C.), after four or five days at 38°C., and 

 after thirty to fifty days at 17.5°C. (after six to twelve days 

 in Russian observations) . Nymphs fed a week later and remained 

 on the host from nine to twelve days (four to six days in Russia) 

 but the time between dropping and molting to the adult stage 

 varied- greatly (twelve to twenty days in Russia) . 



At 35°C . , the molt to females occurred in from eleven to 

 24. days and to males in from twelve to 35 days. At 30°C. both 

 sexes appeared between eleven and 56 days after nymphs dropped 

 from their host. The duration of one generation at 32°C. was 

 estimated at 116 days, but it was conclioded that under field 

 conditions some of these stages may be shorter and there may 

 be three generations a year. 



Parthenogenesis in H. excavatum has been observed by Pervou 

 maisky (194-9) who fovmd That a few Fi females could be reared 

 from eggs laid by females in the absence of males. 



Ecology 



Feldman-Muhsam (1947) observed that unfed larvae and nymphs 

 are much more sensitive to humidity than to temperature. At any 



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