- Workers 1/32"-1/16" long, yellow–brown with brown abdomen.
- Males 1/8" long, black and winged.
- Queens 1/8"-1/4" long, dark red in colour with wings.
- Black eyes. 2 small segments at the pedicel.
- Multi–queen colonies.
- Swarming can take place at any time of the year.
- Winged adults seldom fly so rarely seen. Wings are soon lost after mating.
- Well–defined trails are laid which are often associated with heating systems. Feeds indoors on high protein foods — meat, fats, blood, dead insects, etc.
- Swarming characteristics — new colonies are often formed through nests that have been disturbed e.g., as a result of insecticide spray treatments. Each queen produces up to 3500 eggs in its lifetime.
- Nest locations — deep seated in cavities in heated buildings. Often found in hospitals. Associated with humid conditions. Colonies can range from a few dozen to 300,000 individuals.