The Collaborative International Dictionary of English v.0.48:
calypter \calypter\ n. (Zool.) a scalelike structure between the base of the wing and the halter of a two-winged fly. Syn: alula. [WordNet 1.5]WordNet (r) 3.0 (2006):
calypter n 1: scalelike structure between the base of the wing and the halter of a two-winged fly [syn: alula, calypter]