194 PROCEEDINGS OF THE ACADEMY OF [1899. 



5. Larger, aperture broader and more circular; umbilicus narrow. 



miorhyssa (Dall). 



Smaller, aperture semilunar; umbilicus wider, broadly exposing 



the penultimate whorl hyporhysm (Ckll.). 



6. Max. diam. less than 15 ram. 7 



Max. diam. over 15 mm 8 



7. Basal part of aperture with a couple of obtuse denticles, 



pseudodonta (Dall). 

 Basal part of aperture without any denticles. Ashmuni (Dall). 



8. Deeper colored; basal part of aperture with a more or less bifid 



callosity capitanensis Ashmun and Ckll. 



Paler ; basal part of aperture without any callosity. 



chirica huana ( Dall ) . 



It is a matter of taste how many of the above are to be regarded 

 as species. The characters appear to be uniform in series of speci- 

 mens, and each form inhabits its own special region. There are 

 three distinct groups: the first, consisting of rhyssa, cdtissima, 

 7niorhysia and hyporhyssa, is confined to Sierra Blanca and the 

 immediate vicinity, so far as known ; the second, containing pseudo- 

 donta, Ashmuni, capitanensis and ehiricahuana, occurs in the Capi- 

 tan mountains and vicinity (the forms with the bifid basal callus), 

 in the Jemez mountains and vicinity, and in southeast Arizona 

 (forms without a basal callus on aperture) ; the third, possibly 

 distinct from true AshmvneUa, includes Thomsoniana, from the 

 Santa Fe region. 



