DH. JOHNSTON ON TUB ACABIDES OF BBRWICK8HIBB. 367 



third and sixth or tarsal being the longest, armed with bris- 

 tles not longer than the diameter of the joint, tarsal joint co- 

 noid, rounded at the extremity and rather obtuse. — The an- 

 terior legs are a little distant from the posterior pairs at their 

 insertions. 



This is a little larger than the cheese-mite. I procured my 

 specimens in December, 1848, from the field mouse. It is 

 slow in its motions ; and, when at rest, the fore legs are kept 

 stretched forwards, the lower half being bent towards the 

 oral organs as if to guard them, while the upper half is 

 everted outwards, the whole leg having the figure of the 

 letter S, or rather of a sickle, the base represented by the 

 handle. 



This mite is a member of the family Gamasides, having 

 every character assigned to them by Dug^s. I refer it to the 

 genus Pteroptus, of which five species have been described by 

 Koch, and 1 regret that I am not in a position to say whether 

 any of them is identical with ours. The upper lip con- 

 sists of a double trifid plate placed above the base of the 

 mandibles, the segments spine-like ; and the palpi exactly 

 resemble those of the Gamasides in general, being 5-jointed 

 with the terminal one minute and setigerous, and the penul- 

 timate armed with a moveable spine. 



24. LiELAPS MURIS. 



L. rotunde-ovalis fusca nitida setosa, dorso tuberculato, 

 pedum priorum articulo 2do crassiore et setis duabus validi- 

 oribus armato. Long. \ lin. 



Desc. Mite of a yellowish-brown colour a little darker 

 forwards, roundish-ovate, slightly narrower in front and bisi- 

 nuated on the margin with two stout spines projecting from 

 the central prominence, siuuated on the sides behind the 

 front, bristly ; the back convex, glossy, tubercled, bulged a 

 little at the vertex and depressed behind, where it is semi- 

 transparent: Rostrum triangulate, produced into a stylette 

 and furnished on each side with a mandibular shaft forci- 

 pate at the apex, the chelae colourless neat moveable and 

 curved, the outer claw largest and armed with two denticles 

 on its inner edge : Palpi longer than the rostrum, filiform, 

 colourless, sparingly spinous, the penultimate joint rather the 

 longest, the terminal minute, and both of them bristled: 



