262 



Hominoxious Arthropods 



gg. With eyes. 



h. Anal groove distinct; posterior marginal festoons present. 

 i. Base of the capitulum (fig. 150c) rectangular dorsaUy; 



usually ornate Dennacentor Koch. 



]. 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 43^ to 1 1 5/* in diameter; not over 40 per 

 plate, each plate surrounded by an elevated row of 

 regiilarly arranged supporting cells; white rust want- 

 ing; base of capitxdum distinctly broader than long, 

 its posterolateral angles prolonged slightly, if at all; 

 coxffi I with short spurs; trochanter I with small 

 dorso-terminal blade. Texas, Arizona, etc. D. nitens 







■^'C^to. 



1. 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 30M to 85/u 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 coxae I long, ' 

 lateral spur slightly longer than median; tro- 

 chanter I with dorso-terminal spur. D. albipictus, 

 (= variegatus), salmoni, nigrolineatus. 



