Analysis of genetic data from a multilocus allozyme study, using cellulose acetate gel electrophoresis, of 2 trematode species, Glypthelmins californiensis Stafford, 1905, and Haplometrana intestinalis Lucker, 1931, from Rana aurora and Rana pretiosa, yielded a Nei's genetic distance coefficient between parasites of 0.70 +/- 0.10. This amount of genetic divergence is characteristic of comparisons between congeneric rather than intergeneric trematode species and supports the conclusion, corroborated by morphology and life history, that H. intestinalis is more closely related to some members of Glypthelmins than to any other species.