The vestiture, or hairlike projections of the cuticle, include macrotrichia (setae or setulae), which have an alveolus (socket), and microtrichia, which do not have an alveolus. Setae are the large macrosetae (bristles) that occur at typical positions on the head and thorax in Anastrepha and Toxotrypana. The acrostichal seta is located near the midline of the scutum, medial to the dorsocentral seta. In other flies there may be multiple pairs of acrostichal setae aligned in rows, but in Tephritidae there is at most one pair, slightly anterior to the scuto-scutellar suture. It has sometimes been called the prescutellar seta.