ACARUS SCABIEI. 37 



chitinous nature, which has the appearance of the vertical section 

 of a bell, and is destined to support the powerful penis which is 

 obtusely rounded at its apex, but perforated through the middle. 

 The third pair of feet is otherwise exactly similar to that of the 

 female, but the fourth pair resembles the anterior feet in being 

 furnished with a stalked sucking-cup. In other respects the 

 males exactly resemble the females. 



Bourguignon describes the male sexual organs as follows : 

 On the surface of the abdomen, between the epimera of the 

 hinder legs (i. e., between the comb-like processes which pass 

 from the coxa of the hinder legs in a bent form forwards and 

 outwards), there are the four following sections of structures, 

 which are wanting in the female : 1. A portion placed between 

 the epimera of the last pair of feet, broader at its anterior 

 extremity, narrower behind, then again broader, and soon dividing 

 into two branches running backwards. 2. A portion enclosed 

 in front by branches of the first portion, which has a glandular 

 body at its central point, and thence also divides into two 

 branches, which are at first parallel with those of 1, but after- 

 wards intersect them externally. 3. A portion enclosed by 2, 

 also divided into two branches running backwards, and with a 

 glandular body upon its median line. 4. A portion usually 

 originating in the abdomen, upon and below the plane of this 

 apparatus, and only visible after the destruction of the mite, 

 namely, a filiform structure, uncoiling posteriorly, the penis, 

 which protrudes from its sheath at a little distance from the 

 orifice of the rectum. (See also Kramer, ' Illustrirte Med. 

 Zeitung/ iii, No. 10.) 



The male has also a sucking-cup on the fourth pair of feet 

 instead of a hair, and the epimera of his hinder feet are united 

 by a transverse band. Bourguignon here states that the third 

 and fourth hinder feet of each side are only united by a band, 

 but that the transverse band is wanting, in which he is wrong. 

 In the male, also, the horny appendages of various sizes and 

 thicknesses on the dorsal shield are wanting, which, according to 

 Bourguignon, prevent retrogression and facilitate progression. 

 The male is never whitish, shining, thick, and globular, but blackish, 

 flattened, with a retreating angle at the level of the hind legs; and, 

 lastly, much stronger and more active than the female. The 

 hexapod form exhibits no sexual distinction. The male digs his cave 

 in 10 15 minutes without any pain to his host. Bourguigiioii 



