340 TWO SPECIES OF PARASITIC MITES. 



forwards for a considerable distance to articulate with the epiinera. 

 The second joint is large, with a long and strongly curved outer and 

 a short inner margin. On the outer side, but rather towards the 

 dorsal surface of this joint, three small tubercles are present, bearing 

 at their ends as many short bristly hairs. These are most strongly 

 developed on the first and fourth legs, not being so conspicuous on 

 the second and third. The third joint is smaller and more nearly 

 round, though somewhat longer on its inner than on its outer border. 

 On tins latter border there is a short tubercle and spine present on 

 the first leg, and a pair of blunt spineless tubercles on the fourth. 

 Articulating with the distal end of the third joint is the fourth joint 

 or tarsus, which at its proximal end is comparatively narrow, but 

 after a short distance it suddenly increases to about double its 

 original breadth, forming on the inner side of the first leg a back- 

 wardly projecting spine, which, however, is not present in the other 

 extremities. After thus enlarging the tarsus does not again contract, 

 but continues of about the same size to the end of the joint, when it 

 is sharply truncated, the end being straight or even slightly incurved. 

 In this emargination, but rather towards the dorsal surface of the 

 joint, a short blunt spine takes its origin. On the same joint, 

 but on the extreme outer angle, there is also present a rather 

 strong, slightly curved claw, of about the same length as the spine 

 and with it giving to the leg the appearance of being terminated by 

 two claws. Besides the spine and claw the tarsus is armed with 

 two bristles, one on the inner and one on the outer side. 



Situated immediately under the thin transparent epidermis, and 

 imbedded in the tissues of the body, the epimers&, which are com- 

 posed of strips of light-brown coloured chitin, extend from the 

 anterior angle of the base of the legs towards the middle line of the 

 body, and form with the small pieces of chitin behind the rostrum 

 the framework or skeleton of the trunk. Their principal functions are 

 to serve as supports for the legs and to form points of attachment for 

 the muscles which move them. Those of the anterior pair of legs 

 arise on each side of the rostrum and close to it, and run backwards 

 and inwards for about one-fourth the length of the body, not meeting 

 to form a point, however, as in Sarcoptes minor, but turning sharply 

 outwards and ending abruptly. Those of the second, third and 

 fourth legs are also each of them present as detached bands. The 



