Acarina 263 



kk. Dorso-lateral prolongation of stigmal plate distinct. 

 1. Body of plate distinctly longer than broad; goblet 

 cells of medium size, usually 17.5/4 to 35/4 or 40^ in 

 diameter, appearing as medium sized punctua- 

 tions on untreated specimens, but on the speci- 

 mens treated with caustic potash they appear 

 very distinct in outline, which is not circular; 

 base of capitulum usually less than twice as broad 

 as long, the postero-lateral angles always dis- 

 tinctly prolonged caudad. 



m. Trochanter I with distinct dorso-subterminal 

 retrograde sharp, digitate spur; postero- 

 lateral angles of capitulum pronouncedly 

 prolonged caudal, ii2f* to 160^ long; goblet 

 cells attain 13/1* to 40/1* in diameter; type 



locality California . . D. occidentalis 



mm. Trochanter I with dorso-terminal blade; postero- 

 lateral angles of capitulum with rather short 

 prolongations. 



n. Stigmal plate small, goblet cells not exceeding 

 45 in the male or 100 in the female; scutum 

 with little rust, coxa I with short spurs, the 

 inner distinctly shorter than the outer 



D. parumapertus-marginatus 



nn. Stigmal plate larger; goblet cells over 70 in 

 the male and over 100 in the female; coxa I 

 with longer spurs, inner slightly shorter 

 than the outer; scutum with considerable 



rust D. venustus* 



11. Goblet cells small, rarely exceeding 1 7.6/1*, occasional- 

 ly reaching IQ/A in diameter; on untreated speci- 

 mens they appear as very fine granulations, and on 

 specimens treated with caustic potash they may 

 be difficult to see, but their large number can 

 be determined from the prominent stems of the 

 goblets; surface of outline of the goblets dis- 

 tinctly circular; base of the capitulum usually less 

 than twice as broad as long, the postero-lateral 

 angle distinctly prolonged caudad; spurs of 



coxae I long 



D. reticulatus and electus (= variabilis?} 



ii. Base of the capitulum (fig. 151) usually hexagonal (except 

 in the male of puchellus) ; and usually inornate. 



*Dr. C. W. Stiles considers the species which is responsible for spotted fever distinct from the 

 venustus of Banks, separating it as follows: 



Goblet cells about 75 in the male or 105 in the female. Texas. D. venustus. 



Goblet cells 15? in the male, or 120 in the female; stigmal plate shaped as shown in the figure 

 (figs. 150 a, b). Montana, etc. D. andersoni. 



