P. nevadicus Horn, 1880: 263;

Hatch, 1933: 203; Jeannel, 1933: 251 (assignment to subgenus, as a general statement), 1936: 91 (reduced to subspecies status, as subspecies of P. californicus, not stated as taxonomic change), 1949: 97 (assignment to group californicus, as a subspecies of P. californicus); Peck, 1973a: 113 (type seen; resurrected to species status, not stated as taxonomic change; assignment to group), 1977: 192.

Holotype female [a single specimen in original description, assumed as holotype; designated as lectotype in error in Peck, 1973a] in ANSP [in Jeannel, 1936; original description refers to Horn collection] [now in MCZC].

Type locality: “western Nevada” [State].

Distribution: Canada; U.S.A. (widespread); Mexico: Durango State. Biology: In mammal nests and burrows (especially pocket gophers).

= P. piperi Hatch, 1933: 205, 1957: 42 (no new record); Jeannel, 1933: 251 (assignment to subgenus, as a general statement), 1936: 91, 1949: 97; Peck, 1973a: 113 syn. (holotype seen). Holotype female in USNM (n° 43482). Type locality: Pullman, Washington State, U.S.A.

= P. densus Hatch, 1957: 42 (in key); Peck, 1973a: 113 syn. Holotype male in Hatch collection, USNM. Type locality: Forest Grove, Oregon State, U.S.A.

= P. thomomysi Hatch, 1957: 42 (in key); Peck, 1973a: 113 syn. (holotype seen). Holotype female in UBCZ [in Peck, 1973a; original description refers to Stace Smith Collection, now in UBCZ]. Type locality: Creston, British Columbia Province, Canada.