Acalyptratae Calyptratae The Schizophora are a section of true flies containing 78 families, which are collectively referred to as muscoids, although technically the term "muscoid" should be limited to flies in the superfamily Muscoidea; this is an example of informal, historical usage persisting in the vernacular.

The inflation of the ptilinum (using fluid hemolymph rather than air) creates pressure along the line of weakness in the puparium, which then bursts open along the seam to allow the adult to escape.

When the adult emerges, the fluid is withdrawn, the ptilinum collapses, and the membrane retracts entirely back inside the head.

In the Schizophora, however, the serosa does not develop, but these flies lay their eggs in damp places, such as rotting organic matter.

[1] The absence of schizophoran flies from Cretaceous rocks implies that they likely rapidly diversified during the Cenozoic, with the first appearance of the group during the early Paleogene,[2] around 53 million years ago, with it being estimated that they split off from other flies around 66-65 million years ago.