What is "agathymus"

Agathymus is a genus of butterflies in the skipper family, Hesperiidae. They occur in the North American deserts. The larvae bore in the stems of agave plants.

These butterflies have been treated as members of the disputed skipper subfamily Megathyminae, but are also considered sufficiently distinct to be in their own family, Megathymidae, along with the genera Megathymus and Stallingsia.