PARASITIC GAMASID MITE. 



385 



are present on its surface, six pairs practically forming a longi- 

 tudinal series running down the middle and four other hairs 

 being placed on each side, three of these lateral hairs being 

 marginal. The minute posterior shield is not provided with 

 any hairs, but one or more pairs of minute punctations, which 

 may possibly represent the sockets of hairs, occur on it. 

 On each side of the dorsal surface, a little behind the anterior 

 shield, there are two distinct but very minute platelets, and 

 they are followed posteriorly by about four very inconspicuous 



Text-figure 2. 



Xchoronyssus serpentium, ^ . Dorsal view. 



(obsolete) linear platelets, arranged in a longitudinal series. 

 Numerous hairs are present on the posterior part of the 

 ventral surface, but they are shorter than those on the dorsal 

 surface. Sternal 2ylctte trapezoidal in shape, being much wider 

 than long and furnished with only two pairs of hairs. Genital 

 apertiLre normal in situation and appearance ; it is protected by 

 the usual thin membranous operculum. Gerdto-ventrcd plate long 

 and very narrow, the hinder end being sharply pointed. Anal 



