Flies and butterflies both obtain their nutrition from a diverse selection of substrates such as sap, rotting fruit, trash, dung, and flower nectar using modified mouthparts (proboscis). The proboscis architecture varies among species and has been shown to relate to feeding habits. The purpose of our project is to examine the function of previously unstudied structures on the butterfly and fly proboscises, in particular the dorsal legulae (butterflies) and the prestomal teeth (flies). We hypothesize that the prestomal teeth and modified legulae provide an adaptive advantage when feeding on rotting fruit and sap because the serrations aid in scratching the surface to expose fluids. Our preliminary research includes the examination of microwear patterns on the surfaces of Fruit Rollups ® from which the flies and butterflies feed using scanning electron microscopy and studies of mouthpart movements that might aid in scratching surfaces. We also intend to study the elemental composition of these structures using energy dispersive analysis in search of metal deposits that would provide the mouthparts with more rigidity. Our results could indicate that the some butterflies and flies possess adaptations that aid in fluid uptake from fleshy, porous surfaces, such as rotting fruit.