[Illustration: 150. Stigmal plate of Dermacentor andersoni; (_a_) of male, (_b_) of female. After Stiles. (_c_) Dermacentor variabilis, male; (_d_) Glyciphagus obesus; (_e_) Otodectes cynotis; (_f_) Tyroglyphus lintneri; (_g_) Tarsonemus pallidus; (_h_) anal plate and mandible of Liponyssus; (_c_) to (_h_) after Banks.] gg. With eyes. h. Anal groove distinct; posterior marginal festoons present. i. Base of the capitulum (fig. 150c) rectangular dorsally; usually ornate. DERMACENTOR Koch. j. Adults with four longitudinal rows of large denticles on each half of hypostome; stigmal plate nearly circular, without dorso-lateral prolongation, goblets very large, attaining 43µ to 115µ in diameter; not over 40 per plate, each plate surrounded by an elevated row of regularly arranged supporting cells; white rust wanting; base of capitulum distinctly broader than long, its postero-lateral angles prolonged slightly, if at all; coxæ T with short spurs; trochanter I with small dorso-terminal blade. Texas, Arizona, etc. _D. nitens_ [Illustration: 151. Rhipicephalus bursa, male. After Nuttall and Warburton.] jj. Adults with three longitudinal rows of large denticles on each half of hypostome; goblet cells always more than 40 per plate; whitish rust usually present. k. Dorso-lateral prolongation of stigmal plate small or absent; plates of the adults distinctly longer than broad; goblet cells large, usually 30µ to 85µ in diameter, appearing as very coarse punctations on untreated specimens, but on specimens treated with caustic potash they appear very distinct in outline; base of capitulum distinctly (usually about twice) broader than long, the postero-lateral angles distinctly produced caudad; spurs of coxæ I long, lateral spur slightly longer than median; trochanter I with dorso-terminal spur. _D. albipictus_, (= _variegatus_), _salmoni_, _nigrolineatus_. kk. Dorso-lateral prolongation of stigmal plate distinct.