Thompson and Zumbado (2000) gave a compelte description of the subgenus Mimocalla. This subgenus is readily distinguished from all other groups of Ocyptamus by: 1) strongly petiolate and clavate abdomen; 2) large size; 3) enlarged male genitalia including a modified 4th sternum; 5) vein R4+5 sinuate; 6) vein M1 sigmoid; and 7) metatrochanter with a strong pile tuft. In appearance Mimocalla can only be confused with O. (Theranta) conjunctus, but Mimocalla is readily distinguished by the sinuate vein R4+5 and short antenna (Thompson and Zumbado 2000).
Ocyptamus tristani is similar to capitatus but differs by the presence of a yellow fascia on the 2nd tergum and broader yellow fasciae on the 3rd and 4th terga.