The false stag beetles Diphyllostoma Fall are a group of three species of rare beetles known only from California. Almost nothing is known of their life history beyond that the adults are diurnal; larvae have not been observed.

Their length ranges from 5-9 mm; bodies are elongate, with a generally dull brown to reddish-brown color. Both body and legs are covered with longish hairs.

Originally classed with the Lucanidae, Diphyllostoma have a number of characteristics not shared with any other type of stag beetle, and so in 1972 Holloway proposed a separate family Diphyllostomatidae, which has since been accepted.

Reference

• Mary Liz Jameson and Brett C. Ratcliffe , "Diphyllostomatidae", in Ross H. Arnett, Jr. and Michael C. Thomas, American Beetles (CRC Press, 2001), vol. 2
• B. A. Holloway , "The systematic position of the genus Diphyllostoma Fall (Coleoptera: Scarabaeoidea)" New Zealand Journal of Science 15: 31-38 (1972)