4 A. I>. MICHAEL ON AN UNDESCRlBED 



np), and " Flittcr-mouse " in English," Fleder-maue " in German, 

 " Chauve-souris " in French, &c. ; and that modern classification 

 places the bats between the mice and the moles, certainly with the 

 squirrels and a few other things between the mice and the bats, but 

 very close together. 



This phase of the subject does not quite end here, for upon the 

 squirrel is found another parasite, which, although clearly different 

 from Myobia, is yet nearly allied, namely, Listrophorus, which is 

 also a mouse-parasite, and which, in spite of the marked resem- 

 blance which it bears to Myobia, is, at present, placed in a different 

 main division of the Acarina by the exigencies of modern classifica- 

 tion, the order being now usually divided into two primary groups, 

 the Tracheata and the Atracheata. The two genera unfortunately 

 are separated by this classification of Dr. Kramer's, which is 

 probably the best, because Myobia possesses well-marked and even 

 conspicuous trachea?, chiefly consisting of a main tracheal trunk on 

 each side of the body, considerably branched, and ending anteriorly 

 in two stigmata near the base of the rostrum ; while in Listrophorus 

 trachea? have not been discovered as yet. 



^fyobia is evidently a true parasite, living permanently upon, and 

 at the expense of its host ; the whole life-history of the creature is 

 known, and its embryology and subsequent changes have been ably 

 investigated by Claparede, who did not usually leave much for other 

 people to do after him ; and the whole round of existence was found 

 to be passed upon the unfortunate mouse, or other vertebrate, which 

 the acarid has selected for its board and lodging. The mouth- 

 organs of Myobia are essentially those of a creature feeding upon 

 its host, being composed of two lancet-like maxilla? lying together 

 in a soft tube or lip, and forming a piercing and sucking organ, but 

 without capturing organs, such as are found in the Trombidiino?, 

 Cheyleti, Gamasida?, and other rapacious, predatory Acarina, whose 

 palpi or mandibles are converted into seizing organs. 



It remains to consider the name which should be given to the 

 present species. The much greater numbers which have been taken 

 on tlir Rhinolopkus would seem to point to adopting that genus as 

 ii basis for the specific name ; but, on the other hand, one specimen 

 was found on tin- Scotophilus, and the experience is hardly yet suffi- 

 cient to justify a conclusion as to what bats are infested by it ; nor 

 inusl it l>e forgotten that, where bats are abundant, they usually 

 lijliernate in caverns, or other suitable places, in closely-packed 



