[1][2] The adults are small (less than 1⁄8 inch [3.2 mm] long), black, delicate flies (similar to a fungus gnat) that live for an average of 10 days, feeding on aphid honeydew.

Females deposit 100-250 tiny (1⁄64 inch [0.40 mm]) shiny orange eggs singly or in small groups among aphid colonies that hatch in 2–3 days.

The small, bright orange, slug-like larvae inject a toxin into aphids' leg joints to paralyze them and then suck out the aphid body contents through a hole bitten in the thorax.

[2] A single larva grows up to 1⁄8 inch (0.32 cm) long and kills 4-65 aphids per day.

Once they are placed in the greenhouse they usually emerge from the shipping container as adults to begin egg-laying in 3–7 days depending on temperature.