The Heleomyzidae are a small family of true flies in the insect order Diptera. Over 740 described species of Heleomyzidae occur in about 76 genera and 22 tribes distributed throughout the world; the greatest number occur in the Holarctic region. Around 100 species of Heleomyzidae are found in North America. Larvae feed on decaying plant and animal matter, mushrooms, and various fungi. Most of the subfamilies have been commonly recognized as families in the past, but are now included within the Heleomyzidae. The composition and monophyly of the family continues to be controversial. McAlpine recently combined Heleomyzidae and Sphaeroceridae into Heteromyzidae, but this arrangement has not been widely accepted.