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American Midland Naturalist Monograph No. 1 



flange projecting over the base of the hypostome. Stalks of the chelicerae very 

 long and slender. 



Hypostome. — Long, attenuated, pointed and with the very fine denticles 

 limited to near the apex; denticles not in definite files; viewed in lateral profile, 

 bent, with convex side ventrad. 



Folds. — Coxal and supracoxal folds present. 



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

 ent; dorso-ventral groove absent. 



Sexual opening. — Placed between coxae I. 



Eyes. — Absent. 



Anus. — Large, in an elliptical pattern. 



Matheson (1935) describes the nymph and larva as follows: 





P Si 



Fig. 49. Ornithodoros azteci Matheson. A, Hypostome of adult. B, Leg I of adult. 

 C, Leg IV of adult. D, Engorged larva, ventral view. E, Hypostome and palpi of 

 larva, ventral view. F, Leg I of larva. G, Leg III of larva. 



