THE GENUS DEMODEX. 



29 



Author's measurements : — 



Total length of body (incl. cajjit.) 

 Length of ceplialotliorax-t-eapitiiluin 



„ abdonit'U 



Greatest width of cephalothorax 



„ ,, abdomen . . . 



,, „ capituluni (at base) 

 Length of capitulum 



„ penis (not including curve) 



Large elongated nymplis, length up to 320-350 /x. 



Canestriui's specimens oiD. bovis were of the following dimensions : — 



Nymph up to ^4 mm. in length. 



Host : Cattle (Bos taurus). The specimens described above were collected from 

 A Frican cattle at Zambi, Bas-Congo, by M. E. Van Saceghem (Director of the Veterinary 

 l>aboratory at that locality), who liindly presented them to the Museum. They are well 

 preserved in alcohol and g'ycerine, but' some are slightly distended by the preservative, 

 and it is possible that the dimensions are slightly altered. 



7. DEMODEX EQUI, Railliet, 1895. 

 Demodex folliculorum var. equi, Eailliet, Zool. 2nJ Ed., 1895, p. C39. 



(Plate II. figs. 9-11.) 



? , This species is much wider than is usually the case in the genus, 

 tlie width of the cephalothorax (in mounted specimens) being about a 

 tliird or slightly more than a third of the total length ; the part of the 

 body bearing the fourth pair of legs is the widest. Cephalothorax + 

 capitulum longer than abdomen; the latter has the posterior end 

 rounded off or else bluntly pointed. Capitulum distinctly wider than 



