Wikipedia
The Brachyceran infraorder Muscomorpha is a large and diverse group of flies, containing the bulk of the Brachycera, and, most of the known flies. It includes a number of the most familiar flies, such as the housefly, the fruit fly, and the blow fly. The antennae are short, usually three-segmented, with a dorsal arista. Their bodies are often highly setose, and the pattern of setae is often taxonomically important.
The larvae of muscomorphs (in the sense the name is used here; see below) have reduced head capsules, and the pupae are formed inside the exoskeleton of the last larval instar; exit from this puparium is by a circular line of weakness, and this pupal type is called "cyclorrhaphous"; this feature gives this group of flies their traditional name, Cyclorrhapha.