26 STUDIES ON ACAEI. 



sometimes nearly nine times as long as the width of the cephalothorax. 

 Abdomen about 2| times the combined length of cephalothorax and 

 capitulum. Capitulum wider than long ; the spines on its dorsal 

 surface are short and somewhat curved. 



d . Abdomen about twice as long as the cephalothorax + capitulum. 

 Body more than 6 times as long as the cephalothoracic width. Male 

 sexual orifice situated above the interval between the legs of the first 

 and second pairs. 



Female. Male. 



Total length of body (incl. capit.) 292 /j. 200 /i 



Length of cephalothorax + capitulum .... 82 /i 72 /a 



„ abdomen 210 /x 128 /x 



Greatest width of cephalothorax 30-32 fx. 3-4-36 /a 



„ ,, abdomen 33 ;u — 



„ „ capitulum (at base) ... 27 /a 2.5 /x 



Length of capitulum 23 /x 20 /x 



Host : Field Mouse (Apodemus gylvalictis). 



Note. — In one male specimen the tracheal tubs leading from the capitulum are quite 

 distinct; each is at first double but the two parts afterwards fuse to form a single wide 

 lateral main trunk. 



4. DEMODEX CATI, Megnin, 1877. 

 Journ. Anat. Physiol. 1877, vol. xiii. p. 112. 



(Plate V. fig. 23.) 

 d . Body elongated, being almost 5| times the cephalothoracic 

 width. Abdomen about IJ times as long as cephalothoi"ax-|- capitulum, 

 its posterior end pointed. Capitulum wider than long ; spines on its 

 dorsal surface of the same type as in D. cams, but very minute and 

 inconspicuous. Male genital orifice placed above and in front of legs 

 of second pair. 



? . Body very elongated ; capitulum as in male, but as wide as long. 

 [Female specimens too damaged for a more detailed description.] 

 Author's measurements : — 



Female. Male. 



Total length of body (incl. capitulum) ... — 189 /x 



Length of capitulum + cephalothorax .... 74-77 /x 73 /x 



„ abdomen — llGyu. 



AVidtli of cephalothorax 29 /x 34 /x 



„ abdomen — 31 /x 



„ capitulum 20 /x 24 /x 



Length of „ 20 /u 18-19 yx 



Host: The Cat (Felis domestica). A perfect male specimen and a few damaged 

 specimens collected by the author from a London cat, which did not show any signs 

 of skin-disease. 



