Microtrichia are hairlike projections of the cuticle that do not have an alveolus. They should not be confused with setae or setulae, which have an alveolus. Microtrichia are usually minute and cannot be seen individually except with high powered microscopes or scanning electron microscopes. They occur in patterns so that some surface areas may appear duller or pruinose versus shiny areas that lack them. Cell bcu (= cell cup, "anal cell"), the basal cubital cell, is the basal wing cell bounded anteriorly by the base of vein Cu, apically by vein Cu₂, and posteriorly by vein A₁. In most Tephritidae, vein Cu₂ is concave or has a distinct bend, forming an acute posteroapical extension or lobe on cell bcu.