Erynnis baptisiae, the wild indigo duskywing, is a butterfly of the family Hesperiidae. It is found in North America from southern New England and southern Ontario west to central Nebraska, south to Georgia, the Gulf Coast, and south-central Texas. The species is rapidly expanding its range and abundance by colonizing plantings of crown vetch along roadways and railroad beds. Erynnis lucilius, Erynnis baptisiae and Erynnis persius belong to the "Persius species complex", a confusing group of very similar species.