A survey of many ponds in western Massachusetts has revealed a high percentage of infection with larval trematodes. Collections are being made in some of these ponds every month to study the ecology of the cercarial fauna. Over 3,000 snails have been taken from a small pond in South Amherst, only one of which has been infected with a small species of strigeid cercaria. Since this cercaria has occurred but once, and since as far as can be determined it is specifically different from other known species, it is described here in detail as Cercaria pseudoburti n. sp.