A very informative and useful treatment of the genus, covering the 15 species (+ 35 more subspecies!) of Crossidius as circumscribed at the time of publication.
Includes keys to species, description of species & subspecies, and detailed range info...as well as introductory info on biology, host plants, etc.

According Larry Bezark's 2015 Checklist (see pp. 186-7), two more species have been described since Linsley & Chemsak's 1961 work here:

C. grahami Morris & Wappes, 2013   [Range: Georgia, USA...an interesting disjunct from the western range for the remainder of the genus]
C. mexicanus Chemsak & Noguera, 1997   [Range: Mexico]
Also, three other species treated under Crossidius here were subsequently moved to genus Deltaspis:

C. cruentus Linsley & Chemsak, 1961 → Deltaspis cruentus (LeConte, 1862)
C. nigrescens Chemsak 1959 → junior. syn. of Deltaspis alutacea (Bates, 1885) Chemsak & Linsley, 1974
C. tumacacorii Linsley & Chemsak, 1961 → Deltaspis tumacacorii Chemsak & Linsley, 1974