MITES. 291 



shaped palpi, ending in a minute cheliform process. 

 These palpi it moves about in a very free and active 

 manner, constantly opening and shutting the cheli- 

 form fingers at the extremity. Its motions, in this 

 respect, are very similar to those of the genera 

 Chelifer and Obisium among the pseudo-scorpions. I 

 have occasionally taken this species in collections of 

 dried plants that had been kept in rather a damp 

 place. Either it, or a closely allied species, is 

 sometimes found parasitical on birds : such I have 

 taken from the green woodpecker, differing only 

 from the common kind in being almost quite white, 

 the posterior extremity of the abdomen alone in- 

 clining to yellowish. None of these mites, however, 

 have more than six legs, and possibly they may prove 

 to be only the larvae of some other genus. 



Philodromus limacum.* This mite is parasitic on 

 the larger kinds of slugs, especially the common 

 black slug, on which it may frequently be observed 

 in great plenty. The most striking feature in its 

 history is the circumstance of its not confining its 

 abode to the external surface of the slug, but often 

 retiring within the body of that animal ; effecting 

 its entrance by means of the lateral foramen which 

 leads to the cavity of the lungs. Indeed, I am in- 

 clined to think that this cavity is its principal resi- 

 dence, whence it only comes forth occasionally, to 

 ramble upon the surface of the body. In one in- 



* See London's Mag. of Nat. Hist. vol. iv. p. 538, where I 

 have given a detailed account of the characters and habits of this 

 little mite, from which the above is taken. 



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