This small family is unique to the Neotropics and comprises 36 species in one genus (Macrosoma) from Central and South America.

Members of the family look very much like moths and were only formally recognised as butterflies in 1986. This was partly due to the form of their early stages, which include:

  • eggs that are often spindle shaped like those of some Pieridae
  • caterpillars with forward pointing horns resembling the larvae of Purple Emperor butterflies

The Hedylidae have adults with unclubbed antennae and are similar to geometrid moths but are actually now classified as butterflies, a discovery made in the Museum in 1986.