The life cycle of a predaceous midge (Aphidoletes aphidimyza). Eggs are orangish red, oval, and about 1/80 inch (0.3 mm) long. Larvae develop through three instars, are pale yellow to red or brown, and at maturity are about 1/10 (2.5 mm) long. Pupae are orange to brown, about 1/12 (2 mm) long, and occur beneath plants in litter where they may form cocoons made from soil particles, excrement, and aphid cast skins. Adults are delicate flies with long slender legs.

Illustration from the Natural Enemies Handbook: The Illustrated Guide to Biological Pest Control. Oakland: Univ. Calif. Div. Agric. Nat. Res. 3386, p. 98. (larvae from Peterson 1960, reprinted with permission from Helen H. Peterson; adult from Quayle 1932)