The Brachycera are a suborder of the order Diptera.

[3] Their most distinguishing characteristic is reduced antenna segmentation.

A summary of the main physical characteristics is: Brachyceran flies can also be distinguished through behavior.

The structure of subgroups within the Brachycera is a source of much confusion and controversy; many of the names used historically (e.g., Orthorrhapha) have not been used in decades, but still persist in textbooks, checklists, faunal catalogs, and other sources.

Additionally, most recent classifications no longer use the Linnaean ranks for taxa (e.g., the Tree of Life Web Project), and this creates its own set of problems.