Anastrepha fraterculus and Ceratitis capitata are widely distributed fruit flies that cause significant damage
to fruit crops in tropical and temperate regions. The economic importance of these flies has resulted in
numerous studies of their biology, with particular emphasis on their control and management. However,
various aspects of the biology of these species are still poorly understood. In this work, we used scanning
electron microscopy (SEM) to examine the external anatomy and organization of the digestive system in
these two species. Adult males and females of A. fraterculus and females of C. capitata were dissected in
physiological saline solution, and the digestive tracts were removed and prepared for microscopy. SEM
showed that the crop was covered by a strong muscular layer that consisted of circular fibers connected by
longitudinal fibers; this arrangement was probably related to the post-feeding behavior of these flies in which
the crop contents are regurgitated and reingested. The size of the rectum varied and was probably related to
the different body sizes of the two species.