60 



Genus Ornithodoros 



Body : L. 5 — 6, W. 3 — 35 mm., with sides almost straight and 

 parallel, conical anteriorly, bluntly rounded posteriorly, earthy yellow or 

 dirty brownish red when replete, dorsum and venter covered by large 

 glossy mammillae (150 — 200 /a in size); dorsum bearing large discs. 

 When unfed the dorsal border is raised and thick and the dorsal surface 

 undulating with a prominence over the capitulum, flanked by four sym- 

 metrical depressions; all of these, and other depressions posteriorly, 

 disappear when the tick is gorged. Pre-anal and post-anal grooves, 

 supra-coxal and coxal folds well marked, the coxal folds passing between 

 coxae I and II. Post-anal groove with fine transverse striae. Anal 

 frame almost as wide as long (225 x 200 /m), the valves bearing two to 

 four hairs each. Spiracles conical, 100 fi broad, plate crescentic, 

 situated dorsally on the supra-coxal folds. Eyes absent. Capitulum 

 lying in a deep camerostome or pit, with prominent lateral flap-like 

 borders which move as upon a hinge and protect the capitulum ; ventral 



Fig. 88. O. talaje. A, hypostome (x 160). B, digit, 60 p. I. (Nn. 1896, fig. 34). 



base of capitulum finely wrinkled transversely, permitting (according to 

 Megnin) the mouthparts to be protruded and retracted. Chelicera : 

 digit 60 n I. (Fig. 88 B) with tridentate dorsal process near base of 

 internal article and external article bidentate. Hypostome (Fig. 

 88 .4) emarginate, with many fine teeth distally, followed by dentition 

 2 1 2 covering half its length ; two very long post-hypostomal hairs. 

 Palps with articles 1 — 4 measuring respectively 134, 114, 80, 87 /j, I. 

 Numerous pennate hairs especially on dorsal surface of articles 1 

 and 2, a stout hair at the antero-internal angle of article 1. Legs 

 long and slender; coxae contiguous, decreasing in size from pair I 

 to IV, covered with granulations or mammillae posteriorly; tarsi 

 tapering without marked distal protuberance, unless on pair I; all 

 the articles bear semi-pennate hairs, which are longest on tarsi. 



The foregoing description (condensed from Neumann, 1896, pp. 34- 

 36) is based on the examination of three specimens from Cumana 



