One Panamanian species of sandfly, Phlebotomus vespertilionis, usually associated with bats, has a high overall rate of infection (67.9%) with a trypanosome. Both crithidial and trypanosomal forms are found in the mid- and hindgut but not in the foregut or mouthparts. In the hindgut there may be large numbers of the dominant crithidial forms attached to the epithelium. It has not been determined whether or not the sandfly trypanosome is the same as that occurring in associated bats. Trypanosomes were also found in another species, P. trinidadensis, but at a much lower rate (3.3%). Occasional infections of the hemocoel with gregarines, fungi, and nema-todes have been noted in a number of species.