O. megnini, a widely distributed species, is the type of this genus.
ff. Integument with rounded tubercles or granules; body without stiff bristles. Ornithodoros Koch.
g. Two pairs of eyes; tarsi IV with a prominent subterminal spur above; leg I strongly roughened. On cattle and man. O. coriaceus
gg. No eyes; no such spur on the hind tarsi.
h. Tarsi I without humps above. O. talaje.
hh. Tarsi I with humps above.
i. Tarsi IV without distinct humps above. On hogs, cattle and man. O. turicata
ii. Tarsi IV with humps nearly equidistant ([fig. 142]). Africa. O. moubata
dd. With scutum or shield ([fig. 50]); festoons usually present; coxæ usually armed with spurs, tarsi generally with one or two ventral spurs; pulvilli present in the adults; sexual dimorphism pronounced. Ixodidæ
e. With anal grooves surrounding anus in front; inornate; without eyes; no posterior marginal festoons; venter of the male with non-salient plates. Numerous species, 14 from the United States, among them I. ricinus (fig. [49] and [50]), scapularis, cookei, hexagonus, bicornis. Ixodes Latr. (including Ceratixodes).