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Accurate and non-destructive field identification of the recently separated Hermeuptychia sosybius and H. intricata is integral in determining key life history differences and assessments of population trends. While distinguishing these species is possible through external features, the utility of these features as field marks warrants further investigation involving individuals with wing wear or atypical phenotype. Our objectives were to 1) assess whether three postmedian line (PML) features are reliable identifying characteristics for accurately differentiating the two species in the field, and 2) determine if adult flight-time differences between the two species could additionally inform field identification. In a double-blind survey, five panelists correctly identified 63.73% of individuals (n = 91), with four individual satyrs misidentified by all panelists. Both the generalized linear mixed model (GLMM; logit link) and the ensemble random forest model indicated that the hindwing M1vein feature best predicted correct identifications to species and was the most important variable compared to the forewing M1 vein and hindwing M3 vein features. We also found further evidence of substantial overlap in flight time between both species. Our results indicate that accurate field identification of these species, when co-occurring at a locality, are imperfect. Habitat, time of year, and PML features should be considered collectively, as opposed to using any one of them separately. Depending on the objectives of a particular survey, observers should be conservative in their identifications and avoid definitive identifications when few individuals are present, unless male androconia patches are observed.