i. Short palpi; highly chitinized; unfed adults of large size; coxæ conical; male with a median plate prolonged in two long spines projecting caudad; segments of leg pair IV greatly swollen (fig. [155], [156]). M. winthemi Margaropus Karsch
ii. Very short palpi, ridged dorsally and laterally; slightly chitinized; unfed adults of smaller size; coxæ I bifid; male with adanal and accessory adanal shields ([fig. 139]). B. annulatus. Boophilus Curtis
ff. Palpi longer than broad ([fig. 157]).
g. Male with pair of adanal shields, and two posterior abdominal protrusions capped by chitinized points; festoons present or absent. Several species, among them H. ægypticum ([fig. 140]) from the old world. Hyalomma Koch
gg. Male without adanal shields but small ventral plaques are occasionally present close to the festoons. Many species, a few from the United States ([fig. 157]). Amblyomma Koch
h. Coxa I with but one spine, metatarsi (except I) with two thickened spurs at tips. A. maculatum
hh. Coxa I with two spines; metatarsi without stout spurs at tips, only slender hairs.
i. Projections of coxa I blunt and short. Large species on the gopher tortoise in Florida. A. tuberculatum
ii. Projections of coxa I longer, and at least one of them sharp pointed; second segment of palpus twice as long as the third; coxa IV of the male with a long spine.
j. Porose areas nearly circular; shield of both sexes pale yellowish, with some silvery streaks and marks, and some reddish spots; shield of female as broad as long. A. cajennense (= mixtum).