302 DR. JOHNSTON ON THE ACARIDES OF BERWICKSHIRE. 



and begin to scratch, and make a disturbance ; there being 

 no sun the ants had retired, but it was an ant's nest on 

 which it had taken its station ; the ants immediately came 

 out to attack it, and observing the insect covered with acari, 

 soon destroyed or carried them oiF; when the bee, thus re- 

 lieved from its enemies, carefully cleansed its body and wings 

 with its feet, and then took flight again, evidently much re- 

 lieved.'' Brit. Cyclopoed. Nat. Hist. i. p. 17. 



12. Gamasus testudinarius. 



G. ovatus, scuto dorsi brunneo ovato integro, lateribus 

 anoque albis, pedibus anticis corpore vix longioribus. — Le 

 Gamase testudinaire, Duges in Ann. des Sc. Nat. (1834) ii. 

 27. — Gamasus testudinarius, Gervais in Walck. Ins. Apt. iii. 

 219. — Acarus insectorum rufus, ano albicante, Geoff. Hist. 

 Insect, ii. 623. 



Desc. Body ovate, somewhat angulated at the shoulders 

 and thence narrowed forwards, the back convex, even, bristly, 

 partially covered with an elytrous yellowish-brown ovate 

 skin surrounded by the white soft marginal border which 

 becomes enlarged and broad posteriorly : Venter white and 

 membranous, with a coriaceous sternal plate of an elongated 

 triangular shape, the base towards the circular and raised anal 

 pore : Chelce of the mandibles yellowish-brown with curved 

 points, the external claw with two denticles, and the inner 

 with a single denticle on the cutting edge : Palpi coloured 

 like the legs, the 2d joint somewhat bulged, and the apex 

 armed with bristles ; there is also a moveable seta on the in- 

 ner aspect of the penultimate joint : Legs of a uniform yellow- 

 ish-brown colour, bristly, the first pair about the length of 

 the body, a little longer than the fourth pair which is longer 

 than the intermediate pairs, the second pair stoutest ; 1st 

 joint short and thick, 2d smaller, 3d originating with a con- 

 stricted articulation, incrassated upwards, slightly curved, 

 elongate, 4th shorter than the third, 5th as long as the third, 

 6th elongate slender and straight in the first pair of legs, 

 but decidedly tapered in the others, and in all terminated 

 with a pedicellated vesicle and two very minute claws. 



The bristles of the body are short setaceous and curved. 

 On the vertex, and between the shoulders, a stronger and 

 longer bristle projects, forwards on each side. The bristles 

 of the legs are straight, smooth, and longer than the body 

 ones, especially those of the tarsal joints ; they all point 

 downwards. 



