A B S T R A C T
Light, scanning, and transmission electron microscopy were used to examine the ultramorphology and
ultrastructure of the ileum of Cephalotes atratus, Cephalotes clypeatus, and Cephalotes pusillus. Sections
along the ileum revealed differences among the three main regions: proximal (or pylorus), medial, and
distal. The structural specializations present in the ileumof these three ants have implications especially
to the symbiotic bacteria harbored in this region of the digestive tract. The structural similarities are
conspicuous for the three species examined, suggesting that this is the pattern adopted by the genus