ATOPETHOLID MILLIPEDS — HOFFMAN AND ORCUTT 139 



The only structural difference stipulated for phmius was that the 

 telopodite of the posterior gonopods appeared to be broader than 

 illustrated for michelbacheri, but this difference is probably due to 

 the fact that Chamberlin's drawing was made from a caudal aspect 

 whUe Verhoeft''s was made from the lateral aspect, which naturally 

 shows the narrower dimension of the gonopod. Unless subsequent 

 collections show that two sympatric sibling species occur at Walker's 

 Pass and can be recognized by other constant differences, it seems 

 that phanus must be considered a junior subjective synonym of 

 michelbacheri. 



Atopetholus nigrescens (Chamberlin), new combination 



Onychelus nigrescens Chamberlin, 1923, pp. 406, 407, fig. 46 (male holotype in the 

 California Academy collection, from Coronado Island, Gulf of California, 

 collected by J. C. Chamberlin). 



The original account of this species is not as detailed as it should 

 be, and the present generic allocation must be regarded as tentative. 



Atopetholus pearcei Chamberlin 



Atopetholus pearcei Chamberlin, 1950, p. 6, fig. 3 (male holotype in the Cham- 

 berhn collection, from Oildale, Kern County, California, collected by W. M. 

 Pearce on January 19, 1950). 



The description of this species compares it only with A. fraternus, 

 from which it differs in shape of the posterior gonopod — 



such as in the smaller, almost obliterated anterior marginal lobe and in the 

 tooth at proximal end of the posterior marginal lobe, this being acute and directed 

 nearly at right angles to the long axis of the telopodite instead of being blunt 

 and directed proximad parallel with the axis. 



Genus Watichelus Chamberlin 



Watichelus Chamberhn, 1949, p. 169. — Loomis, 1949, p. 241. 



Type species: Onychelus smithi Chamberlin, by original desig- 

 nation. 



Diagnosis: An atopetholid genus characterized by the presence 

 of a distinct mesially directed branch or process on the telopodite of 

 the posterior gonopod, and by the absence of a secondary process 

 from the telopodite of the anterior gonopods. In other respects the 

 genus is quite similar to Atopetholus, so far as can be determined from 

 published accounts. Loomis (1949) mentioned that the lateral ends 

 of the collum tend to be bent caudoventrad in species of Watichelus, 

 and this condition may also be found to be a diagnostic character 

 when all the species of Atopetholus are inspected for this particular 

 detail. In A. angelus at least (fig. 2,d), the end of the collum is 

 nearly symmetrical and directed ventrad. 



