H. F.  Howden and Young, O. P., ?Panamanian Scarabaeinae: taxonomy, distribution and habitats (Coleoptera, Scarabaeidae).?, Contributions to the American Entomological Institute, vol. 18, pp. 1-204, 1981.

O. P.  Young, ?The attraction of neotropical Scarabaeinae (Coleoptera: Scarabaeidae) to reptile and amphibian fecal material?, The Coleopterists Bulletin, vol. 35, pp. 345-348, 1981.