Biology of H. inenyiis 547 



Remarks upon the exceptional behaviour of H. inermis. 



H. inermis offers an exception to all the ticks whose life-histories we 

 know in that it gorges with remarkable rapidity both in the larval and 

 nymphal stages. It is the rule in Ixodid ticks for all stages to remain 

 attached to the host for several days. In Argasidae we do not know of a 

 species where the larvae feed as rapidly as does the larva of H. inermis 

 although the nymphs, 0. megnini excepted, are rapid feeders (see 

 pp. 81-104, 325-345 of this work). Whilst this habit of rapid feeding 

 may favour the survival of the species, the long time required for the 

 process of oviposition and for metamorphosis from eg^ to larva and 

 from nymph to adult must exert a contrary effect. This phenomenon 

 observed in H. inermis by Brumpt is very interesting and worthy of 

 attention. 



Insect parasites of H. inermis. 



A chalcidid called Ixodiphagus caucurtei du Buysson, 1912 (p. 246) 

 was discovered by Brumpt in the nymphs of Ixodes ricinus in France 

 and raised by him to the seventh generation in the laboratory. This 

 insect attacks the nymphs of H. inermis. Whereas scarcely 1 % of 

 these nymphs become infested, all of the nymphs of /. ricinus, Derma- 

 centor venustus, D. reiicidatus and Rhipicephalus sanguineus in which 

 the parent /. caucurtei deposits her offspring, die and yield imagines 

 of Ixodiphagus. 



