LOUSE MITES, 317 



,\ASE This species, according to Claparede, is almost entirely con- 

 fined to the house mouse. He on one occasion, but only once, 

 met with two examples on the field mouse. He notices a 

 curious fact regarding the distribution of it, and Myocoptes 

 musculinus on mice, which cannot fail to remind the reader of 

 the assignment of two different species of lice respectively to the 

 head and body of man. He says that this distribution in mice is 

 regular to a degree. The Myobia musculi lives only upon the 

 snout, the head, round about the ears, and, in an exceptional way, 

 down towards the throat, but scarcely ever further down. The 

 Myocoptes, on the contrary, confine themselves almost entirely 

 to the abdominal region, although sometimes they wander to the 

 back and sides. Usually there exists a somewhat broad neutral 

 region or zone which separates them from one another; where 

 no parasites are to be found. This species is more easily found 

 than the other, because of its greater size ; in this respect 

 reversing the rule with the Pediculi on man, when the smallest 

 species is found on the head, and the largest lives on the body. 



Genus Otonyssus {Kolenati, Kentniss der Arach. in Sitz. Zool. 

 Bot. Akad. Wiss. Wien, 1858, p. 69). 



This genus was founded by Kolenati for a type of acarids that 

 seem specially told off for living on the ears of bats. While 

 placing it among the Pteroptidse he seems to have regarded it as 

 a link between the Dermanyssi and them, and it certainly has 

 some of the characters of each. It has the sac-like body of 

 the Dermanyssi, and at least one character of the Pteroptidse, 

 the possession of bristles formed after the fashion of those of 

 that genus, that is, jointed like the hairs of the bats themselves; 

 and if we had nothing to go by but the details given by Kolenati, 

 we should have been greatly puzzled where to place them if not 

 where he has. But we have the advantage of an exhaustive 

 account, and very careful facsimile sketches in all its parts of a 

 species which we cannot doubt to belong to this genus, published 



