The aculeus is the elongate, sclerotized, apical part of the ovipositor. Its base is attached to the eversible membrane and these can be retracted into the oviscape. If the aculeus is not everted or visible through the oviscape as is sometimes possible in specimens in alcohol, the terminalia must be dissected to examine the aculeus. Its length is measured from its base, where it connects to the eversible membrane, to its extreme apex. The oviscape is the elongate, tubular or conical, basal part of the ovipositor. It is formed from the fused tergite and sternite of segment 7. It bears a pair of spiracles laterally, and a pair of flangelike lobes basolaterally. Its length is measured ventrally along the midline.