S04 DR. JOHNSTON ON THE ACAllIDES OF BERWICKSHIEB. 



marginibus solis membranaceis albidis, pedibus anticis cor- 

 pore longioribus.—G. marginutus, Lutr. Gen. Crust, et Ins. i. 

 148. Leach in Edin. Encyclop. vii. 415 ; and in Sam. En- 

 torn. Conip. IJJl. Lam. Anim. s. Vert. v. 59 : 2d edit. v. 77. 

 — Le Gamase borde, Dugbs in Ann. desSc. Nat. (1834) ii. 

 26. 



Dksc. Mite of the size of G. coleoptratorum, of a chesnut- 

 brown colour, the venter, rostrum, palpi and legs a shade 

 lighter than the back : Body ovate, narrowest and rostrate in 

 front, edged behind with a colourless pellucid narrow border, 

 sparingly covered with short curved brit-tles, the back a little 

 convex, glossy, with a few irregular punctures or foveo- 

 la3, the venter entirely coriaceous, striolate like the ends of 

 the iingers, with the anus almost marginal ; the sternc^l plate 

 in the form of an escutcheon with the point forwards : Bos- 

 trum porrect, triangulate, sharp-pointed, the chelce of the 

 mandibles dark-brown : Palpi rather longer than the ros- 

 trum, and originating from its base, curved at the bristly 

 apex, the 1st joint curved, the 2d incrassated and bulged on 

 its inner aspect : Legs bristly, the first pair a little distant 

 from the others at their insertions which are close together ; 

 first pair slender and longer than the body, the fourth pair 

 next in length, the second and third nearly equal, but the 

 second are considerably thicker than any of them : Of the 

 first pair the 1st and 2d joints are thick and abort, the third 

 elongated and narrow at its origin, the 4th and 5th shorter 

 than the 3d and almost equal, the 6th elongate, slender, and 

 filiform, armed with longer bristles, and terminated w^ith a 

 pedunculated and lobulated vesicle ; the tarsal joint of the 

 other legs is tapered, and the vesicle is deeply two-lobed, and 

 furnished with stronger claws, each vesicular lobe being itself 

 emarginate. The structure is exceedingly beautiful. 



This mite is also common, and has the same habits as G. 

 testudinarius, to which it is nearly related. I find it under 

 slates, &;c., on warm borders in gardens, and in hot-beds. It 

 runs quickly, holding the long fore-legs forwards as if they 

 were antennae, and then their length appears proportionably 

 longer to the body than they do when the insect is under the 

 microscope. 



In the Rbgne Animal, iv. 282 and 285, Latreille has refer- 

 red this mite to his genus Macrocheles, and also to Gamasus, 



