The arista is part of the highly modified flagellum of the antenna in Tephritidae and most Cyclorrhapha. It is a slender, hairlike structure that extends from the dorsal side near the base of the first flagellomere. It comprises the second and third flagellomeres [?? check McAlpine], which are very small, and the greatly elongated and very slender xx flagellomere. In Anastrepha and Toxotrypana the arista is pubescent, i.e., it bears numerous short hairs.