SOME PAEASITIC ACAEI. 



405 



Grois-iOMEKUS* MUScuLiNus, Dov. gen. et sp. (PI. XXVI. fig. 9.) 



Colour. — Semitransparent white. 



Texture. — Mucli that of the ordinary Sarcoptidae, i. e. smooth 

 and leathery, not polished. The skin is marked more or less 

 with excessively fine wrinkles or striations, so fine that they are 

 very difficult to see. 



Form Sfc. — Body almost oblong, but somewhat narrower poste- 

 riorly than anteriorly ; there is not any clear demarcation between 

 cephalothorax and abdomen. The rostrum projects, but is bluntish; 

 a pair of mandibles may sometimes be seen projecting from the 

 mouth-opening. The rostrum bears a pair of fine hairs. The 

 body is much compressed dorso-ventrally, and is divided into 

 four lobes on each side, the hind lobe showing a slight tendency 

 to be bifid. On the posterior margin there is a slight indenta- 

 tion above the anus, which is almost terminal, but slightly on the 

 ventral surface. From the hind margin spring a pair of long 

 hairs directed backward, they are fully two thirds of the length 

 of the body ; immediately below them are another pair of similar 

 hairs proceeding from lobes on the ventral surface ; as this under 

 pair is entirely concealed by the upper pair, when viewed from 

 above, it is not shown in the figure. The legs are short, and are 

 the great peculiarity of the creature ; they are all alike and all 

 directed forward, the fourth pair usually more so than is shown 

 in the figure, where they are spread out. They consist of five 

 joints ; the femur is very large and singular in shape, it projects 

 beyond the body and bends suddenly at rather less than a right 

 angle, so as to form an advancing corner which completely alters 

 the direction of the leg. The more distal joints become gradually 

 smaller ; the tarsus is terminated by a small claw, smaller in pro- 

 portion than can be shown in a drawing the size of fig. 9, and 

 there is another small chitinous projection close to it which may 

 be regarded as a mere peg or a second claw ; I am inclined to 

 look on it in the former light. There are hairs on the underside 

 of each joint of the leg and one or more on the upperside of 



mm. 



Length about 



Breadth about 



Length of legs (all pairs) about 



•155 

 •105 

 •035 



* yh)via, an angle ; fxrjpbs, the thigh. 



