A. ve8pertiUonis 35 



There is no extant description of the adult of this species. Wheler 

 (1899, p. 12) described a specimen at the British Museum which he 

 believed to be adult, but we have examined it and find it to be a 

 nymph, probably in the second stage. Lounsbury has kindly lent us 

 a mature ? of the form, recognised by Neumann as at least only a 

 variety of A. vespertilionis, which infests penguins at Queenstown, 

 Cape Colony. The following description refers to this specimen : 



Female : L. (hood not included) 7'4, W. 8 - 8 mm., broad oval, much 

 depressed, irregularly convex in the middle of the dorsum, red-brown 

 with narrow reflexed margin of reddish-yellow colour, the integument 

 entirely covered with very fine, conical, sharp granulations, except on 

 the discs, which are arranged as shown in the figure (Fig. 48). The 



Fig. 48. Argas vespertilionis ? , L. 7'4 mm. Venter (see text). Original, N. and W. 



anterior margin projects in the form of a triangle on a level with the 

 dorsum, and from beneath this projection a rounded, yellow convex hood 

 proceeds forward and downward, visible dorsally, and concealing the 

 capitulum. Venter : anus at about the middle of the body ; supra-coxal 

 fold well-marked, short, extending from the sides of the hood to the 

 posterior ends of coxae IV. Coxal folds well-marked, narrow ; very 

 numerous, small, radially arranged discs. Vulva : a very broad slit 

 between the posterior ends of coxae I, much wider than the basis 

 capituli and reaching the coxae on either side. Behind the anus, at a 

 distance of about three times its diameter, there is a remarkable paired 

 organ (see Fig. 49) consisting of two narrow, deep, crescentic clefts, on 

 each side of the middle line ; each cleft lies in an area of modified 

 integument, free from mammillae ; behind the cleft the area is finely 

 punctate, while in front, on its concave border, it is finely striate 

 at right angles to the direction of the cleft. (This structure is also 

 observable in the nymphs.) Capitulum very salient ventrally, with 

 very long base and extremely small appendages ; hypostome narrow, 



3—2 



