Hall (1976) is the most comprehensive semi-recent work on the genus I've found, and while it has useful keys, there are no photos or diagrams. This genus is very well represented in the CAS collection so it would make a great photographic project.
CAS
Lepidanthrax actios
Lepidanthrax agrestis
Lepidanthrax angulus
Lepidanthrax arnaudi
Lepidanthrax borius
Lepidanthrax californicus
Lepidanthrax calyptus
Lepidanthrax campestris
Lepidanthrax chalcus
Lepidanthrax diaerectus
Lepidanthrax disjunctus
Lepidanthrax ellipus
Lepidanthrax eremicus
Lepidanthrax euthemus
Lepidanthrax exallus
Lepidanthrax hesperus
Lepidanthrax homologus
Lepidanthrax hypomelus
Lepidanthrax inauratus
Lepidanthrax lautus
Lepidanthrax leucocephalus
Lepidanthrax linsdalei
Lepidanthrax luminis
Lepidanthrax meristus
Lepidanthrax mimus
Lepidanthrax oribates
Lepidanthrax proboscideus
Lepidanthrax utahensis
BugGuide
Lepidanthrax arnaudi (CA Photo)
Lepidanthrax californicus (CA Photo)
Lepidanthrax eremicus (CA Photo)
Lepidanthrax inauratus (CA Photo)
Lepidanthrax linsdalei (CA Photo)
Lepidanthrax actios
Lepidanthrax agrestis
Lepidanthrax angulus
Lepidanthrax arnaudi
Lepidanthrax borius
Lepidanthrax californicus
Lepidanthrax calyptus
Lepidanthrax campestris
Lepidanthrax coquilletti
Lepidanthrax diaeretus
Lepidanthrax ellipus
Lepidanthrax eremicus
Lepidanthrax euthemus
Lepidanthrax exallus
Lepidanthrax hesperus
Lepidanthrax homologus
Lepidanthrax hyalinipennis
Lepidanthrax hypomelus
Lepidanthrax lautus
Lepidanthrax leucocephalus
Lepidanthrax linsdalei
Lepidanthrax meristus
Lepidanthrax mimus
Lepidanthrax oribates
Lepidanthrax proboscideus
Lepidanthrax symmachus
COMBINED
Lepidanthrax actios
Lepidanthrax agrestis
Lepidanthrax angulus
Lepidanthrax arnaudi
Lepidanthrax borius
Lepidanthrax californicus
Lepidanthrax calyptus
Lepidanthrax campestris
Lepidanthrax chalcus
Lepidanthrax coquilletti
Lepidanthrax diaerectus
Lepidanthrax diaeretus
Lepidanthrax disjunctus
Lepidanthrax ellipus
Lepidanthrax eremicus
Lepidanthrax euthemus
Lepidanthrax exallus
Lepidanthrax hesperus
Lepidanthrax homologus
Lepidanthrax hyalinipennis
Lepidanthrax hypomelus
Lepidanthrax inauratus
Lepidanthrax lautus
Lepidanthrax leucocephalus
Lepidanthrax linsdalei
Lepidanthrax luminis
Lepidanthrax meristus
Lepidanthrax mimus
Lepidanthrax oribates
Lepidanthrax proboscideus
Lepidanthrax symmachus
Lepidanthrax utahensis