su 



DB. JOHNSTON ON THE ACARIDES OF BEBWICZSHIRE. 



at rest I have seen it clean its legs, or rather the tarsi, by put- 

 ting them between the mandibles and as it were nibbling 

 them. On one occasion the process was this : — the foot of 

 one anterior leg was cleaned, then one of the third pair, then 

 the front leg of the opposite side, and then the third leg 

 which had been previously cleaned ; but there was no uni- 

 formity in its proceedings in this respect. The little crea- 

 ture seemed fond of the work, and did it with admirable 

 neatness. 



The mite belongs to the same group as the Ac. longicornis 

 and littoralis. 



19. HyDRACHNA NAiCA. 



H. orbicularis albescens maculis fuscis fusfe signata, oculis 2, 

 pedibus pellucidis albis sparse spinosis, palpis articulis infe- 

 rioribus crassis minutissime serrulatis. 



Desc. Bod^ subglobose, even and smooth, whitish or cream- 

 coloured, marked with several dusky-brown spots, three in 

 front united together by a lighter shading and thus forming 

 a fascia produced behind on the back by a jutting down of 

 the middle spot, two large ones behind of a subquadranglar 

 shape, and a small spot on each side with difficulty distin- 

 guishable : Venter convex, smooth, the anterior half brov^^nish, 

 the posterior half whitish, and running up like a sinus into 

 the dusky colour : E^es two, black, very distinct, placed for- 



ward on the back, one on 



with brown, gently tapered. 



each side of the mesial spot: 

 Palpi (Fig. a) pediform, pro- 

 portionably large, thicker than 

 the legs, 4-jointed, the 1st and 

 2d joints thick and short, mi- 

 nutely serrulated on the outer 

 edge, a rough or granulous 

 mucro at the articulation of 

 the first joint, 3d joint elon- 

 gate and slender, 4th small 

 and unquiform, and terminat- 

 ed with two minute claws: 

 Le^s 8, homologous, all of them 

 much longer than the body, of 

 a uniform clear watery colour, 

 sometimes veiy faintly tinted 

 'ather sparingly bristled : all 



arise from the venter in front, are near each other at their 



