Reference
C. R. Osten Sacken (1895): On the terms Calypteratae and Acalypteratae, Calypta and Calyptra, as they have been used in Dipterology. (A Supplement to my article: Notice on the terms tegula, antitegula, squama and alula in the Berl. Ent, Zeitschr. 1896, p. 285-288), – Berliner Entomologische Zeitschrift – 41: 328 - 338.