114 
THE EXTERNAL ANATOMY OF THE SARCOPTES 
OF THE HORSE 1 . 
By P. A. BUXTON, M.A., F.E.S., 
Fellow of Trinity College, Cambridge. 
(From the Quick Laboratory, Cambridge.) 
(With Plate VII and 22 Text-figures.) 
CONTENTS 
Introduction 
PAGE 
114 
Adult female 
115 
Dorsal surface . 
118 
Ventral surface 
123 
Capitulum 
125 
Legs . 
130 
Male 
133 
Immature female 
139 
Nymph 
141 
Larva 
141 
Egg .... 
143 
Dichotomous key 
144 
Technique 
144 
Bibliography 
145 
Abbreviations . 
145 
INTRODUCTION. 
Warburton (1920) has recently published a survey of our present knowledge 
of the mites of the genus Sarcoptes’, from his survey it is clear that in spite of 
all the work that has been done upon these mites, much of it by most pains¬ 
taking anatomists, we are still without an accurate knowledge of the anatomy 
of any one species of Sarcoptes. This is, in part at any rate, due to the fact 
that some of the best work was done, by Robin and others, between 1860 and 
1865, at a time when microscopes and technique were by no means as highly 
developed as they now are. 
This paper is an attempt to carry forward an investigation, the main lines 
of which have been indicated by Warburton; to describe as accurately as 
possible the anatomy of one Sarcoptes, that of the horse, and to illustrate its 
structure. A detailed knowledge of the structure of one species of Sarcoptes 
is desirable in order that the validity of the numerous very similar species maybe 
settled once and for all. In this paper I purposely avoid reference to systematic 
1 Work done with the aid of a grant from the Ministr}' of Agriculture and Fisheries. 
