[4] Hylaeus anthracinus is colored black and of medium size.

Males have a large facial yellow spot whereas females are completely black.

[2] Hylaeus anthracinus is found in coastal and lowland dry forest.

Populations are now only known from the islands of Hawaii, Kahoolawe, Maui, Molokai and Oahu.

Threats to the species include habitat degradation by nonnative animals and plants, predation by nonnative insects, fires and climate change.