Using scanning electron microscopy, we examined external and internal surfaces of labella of several species of Blepharoneura, Neotropical fruit flies that rasp and cause damage to plant surfaces. Blepharoneura has blade-like and brush-like pseudotracheal ring tips. By examining the internal surface of the labellum, we discovered that rings that bear blades are highly modified structures that no longer function as braces of the pseudotracheal canals. These robust structures may represent adaptations for scarifying plant tissues, and activity that has never been reported for other flies.