Blow flies have the same basic life cycle as the house fly, with white eggs, three larval instars, pupae and adults.

The rates of development are poorly documented, but most develop through a complete life cycle in 10–20 days at various temperatures.

Usually the larvae will be found in clusters in a suitable microhabitat. The larva is shaped grossly like the house fly larva, but the cephalopharyngeal skeleton has stout, wide mandibular sclerites and mouthhooks; the posterior spiracles are distinctive and there are small fleshy prominences posteriorly around the area of the spiracles (Figures 6E–G and Figures 7E–F ).