Calypter

A calypter is either of two posterior lobes of the posterior margin of the forewing of flies between the extreme posterior wing base and the alula, which covers the halteres.^[1]

A Tachina sp. fly showing white calypters at the base of the wings

Calypter of a Tachinid

The lower calypter is the proximal calypter (synonyms: squama (of some authors), tegula) and the upper calypter is the distal calypter (synonym: squamula).^[2]

Species of the subsection Acalyptratae are noted for lacking calypters.^[3]