JSTOR

Clark, W.E. 1987. Revision of the Nearctic species of Pseudanthonomus Dietz (Coleoptera: Curculionidae). The Coleopterists Bulletin 41(3): 263-285.

Abstract (part):
Weevils of the genus Pseudanthonomus were examined in connection with ongoing revisionary studies on the subfamily Anthonominae (see Clark and Burke 1985, 1986). When Dietz (1891) established the genus Pseudanthonomus he observed that the species "resemble each other very closely" and "are difficult to distinguish." The species, as delimited by Dietz (1891), Pierce (1908) and Blatchley (1916), have been difficult to distinguish, primarily because specimens these authors worked with, and considered to represent 14 species, actually represent only seven.