The two pairs of frontal bristles curve outward and scattered interfrontal setulae are present.

Coelopids are found in the wrack zone of temperate seashores where the larvae feed on rotting seaweed.

The females lay their eggs in small batches into fresh alga banks.

Pupation is seldom in the algal substrate that soon collapses, but more frequently in the highest sand layers.

Larvae and pupae have numerous predators, including birds and the staphylinid Aleochara and suites of parasites confined to algal banks.