Biology of I. ricinus 299 



Experiment I. 10. x. 1905. Many larvae were placed on a hedgehog in a 



tick-proof cage. 



13. „ 68 larvae dropped off' gorged. 



14. „ 365 „ „ „ „ 

 J 6- „ 60 „ „ „ „ 



18. i. 1906. Nymphs began to emerge from the larval skins. 



3. vi. „ Thirty of these nymphs were placed on a hedgehog. 



7. „ 10 nymphs dropped off gorged. 



" - 1) H !! >] h » 



Experiment II. 18. x. 1905. Many larvae were placed on a hedgehog. 



23. „ 250 larvae dropped off gorged. 



24. „ 26 „ „ „ „ 

 18. I. 1906. Nymphs began to emerge. 



1. viii. 1906. 50 nymphs were placed on a hedgehog. 

 5. „ 20 „ dropped off gorged. 



It follows that the larvae remain attached to the host for 3-6 days, and 

 the nymphs for 4-5 days, when raised on hedgehogs in the laboratory 

 at a temperature of about 15° C. 



These results are in agreement with the statement by Kossel, 

 Schiitz, Weber and Miessner (1903, p. 40), that larvae remain 3-6 days 

 and nymphs remain 3-5 days upon the host before they become replete. 

 These authors raised the ticks on cattle and guinea-pigs. Samson 

 (1909, p. 186) reports that larvae and nymphs remain attached for four 

 days to man, and as long as 10-14 days to lizards. 



Adults. Bertkau (1881, p. 145) reports that he once placed a 

 hungry </" and % upon his arm, with the result that the £ remained 

 attached for only eight hours whilst the $ remained upon him for eight 

 days. Kossel and his colleagues once saw hungry Js readily attack a 

 guinea-pig upon which they were placed ; they state that the $ renmins 

 attached for a week. According to Sainson (1909, p. 216), the $ remains 

 upon the host for 8-14 days. The fact that the </" remains attached to 

 the host but for brief periods explains why it has not as yet been 

 observed to attack the host under other than experimental conditions. 



Site of attachment on the host. Kossel and his colleagues (1903, 

 p. 39) state that all stages of the tick may be observed on cattle. The 

 larvae and nymphs attack the beast about the head on the muzzle, 

 eyelids and ears, and likewise on the udder. When placed experimentally 

 upon cattle they attack any part of the host's body. Adult ticks attach 

 themselves chiefly on the flanks, inside the legs, on the neck, udder, and 

 in the pit about the anus and vulva. Males are frequently found 

 running about upon the skin, but they have not been found sucking 

 blood from cattle. They are frequently found in coitu with attached 



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