Cooley & Kohls: Argasidae of N. America, etc. 91 



Ornithodoros stageri Cooley and Kohls, 1941 



Plate 9. Figs. 41 and 42 



1941 (b). Ornithodoros stageri Cooley and Kohls, original description, pp. 589-592, with 

 figures. 



Sexes dissimilar; adults and nymphs dissimilar. 



FEMALE 



Body. — Oval, wider behind, approaching a point in front; tips of the palpi 

 often visible from above. Range of sizes from 5.3 x 3.4 to 3.3 x 2.4. 



Mammillae. — Relatively large, few in number, and not crowded; irregular 

 in shape, their tops convex, smooth, often with radial ridges on their bases. 

 A few have a single, faint pit on the top which may or may not have a short, 

 fine hair. 



Discs. — Distinct, depressed, large, mostly circular. Present also on the 

 venter where they are in a lineal arrangement in or near the preanal, trans- 

 verse postanal, and median postanal grooves. 



Legs. — Moderate in length and size; surface nearly smooth, shining, with 

 hairs moderate in number and in length. Subapical dorsal protuberances and 

 dorsal humps absent. Length of female tarsus I, 0.66; metatarsus, 0.48. Length 

 of female tarsus IV, 0.84; metatarsus, 0.75. (Length of male tarsus I, 0.45; 

 metatarsus, 0.3. Length of male tarsus IV, 0.63; metatarsus, 0.54.) 



Coxae I and II a little separated; all others contiguous. 



Hood. — Negligible or absent. 



Camerostome. — Faintly indicated. 



Cheeks. — Small, and somewhat variable in shape; usually oval and attached 

 along one side of the broader portion. (Absent in the male.) 



Capitulum. — Basis capituli about as wide as long; surface irregular with 

 transverse wrinkles. With two or three long, barbed hairs on each side on the 

 lateral walls a short distance from the insertion of the palpi, and a pair of 

 hairs back of the posthypostomal hairs, which are more separated and smaller. 

 Palpal article 1 with its surface a little roughened and with a narrow flange 

 projecting over the base of the hypostome. Articles 2, 3 and 4 free. 



Hypostome. — Notched in both sexes, narrower in the female than in the 

 male, with the principal denticles arranged 2 /o with the four files approximate- 

 ly equidistant. Length in both sexes about 0.22. 



Folds. — Coxal and supracoxal folds present, the latter continuous from 

 side to side in front. 



Grooves. — Preanal, transverse postanal, and median postanal grooves 

 present; dorso-ventral groove absent. 



Sexual opening. — Placed at the level of the intervals between coxae I 

 and II. 



