Cooley & Kohls: Argasidae of N. America, etc. 95 



Ornithodoros dyeri Cooley and Kohls, 1940 

 Plate 9, Figs. 43 and 44 



1940. Ornithodoros dyeri Cooley and Kohls, original description, pp. 925-928, with 

 figures. 



Sexes similar; nymphs and adults similar. 



ADULT 



Body. — Length, 5.5, width, 2.1. Color (living) yellow-brown. Elongated, 

 sides parallel, anterior end pointed, posterior end rounded. Flattened on top 

 and marginated. Viewed in lateral profile the body is nearly straight. Entire 

 dorsum bounded by two continuous ridges which are essentially parallel and 

 with a third (inner) incomplete ridge on each side, plainer in early stage 

 nymphs. Ridges less elevated in the later stage specimens. Within the ridges 

 the surface is irregular due to short ridges and subcircular elevations. In the 

 anterior dorsal area is a distinct median, smooth hump raised above the level 

 of the lateral margins, and anterior to it a deep depression near the parallel 

 marginal ridges. 



Mammillae. — Indefinite or absent though there are present small, irregular 

 elevations on the surface. 



Hairs. — A few very fine, short hairs are scattered on dorsal and ventral 

 surfaces. 



Legs. — Moderate in length, small, micromammillated. Fine, short hairs 

 scattered over the legs; those on ventral surface of the tarsi larger and in two 

 parallel rows. All tarsi without subapical dorsal protuberances or dorsal humps. 

 Stalk of the pulvillus and claws progressively longer on legs I to IV. Femur 

 of leg IV notably long — longer than femur III. Length of femur IV, includ- 

 ing trochanter, 1.08; that of leg III, 0.72. Length of tarsus I, 0.54; metatarsus, 

 0.48. Length of tarsus IV, 0.69; metatarsus, 0.60. 



Coxae. — Coxae I and II separated; all others contiguous. Surfaces irregular 

 and micromammillated. Hairs absent except a row near the articulation with 

 trochanter on coxae II, III, and IV. 



Hood. — A true hood absent but with a median ridge extending from the 

 mouth parts to the anterior margin. 



Cheeks. — Pyriform, attached along one side, with the broader end in front 

 and together with the end of the ventral median ridge forming protection for 

 the mouth parts. 



Capitulum. — Basis large, broader than long; surface having micromammil- 

 lae and distinct transverse wrinkles. Surface of palpal article 1 irregular and 

 with a narrow, knife-edge flange on the median side overlapping the base of 

 the hypostome; other articles free. 



Hypostome. — Short, broad, truncate, with sides nearly parallel; posthypo- 



