Strymon solitario Grishin & Durden, new species is described from southwest Texas, USA. This serapio group species of Strymon is distinguished from its closest relatives by a combination of: (1) restricted areas of light scales basally from submarginal darker lunules on the ventral hindwing—with these light macules not reaching 1/3 of the distance between the lunules and postmedian orange band; (2) small oval well-separated orange macules in the postmedian ventral hindwing band; (3) the presence of postbasal orange macules on the ventral hindwing in some specimens; (4) limited to almost absent violet blue dorsal wing overscaling; (5) occasional orange overscaling on the dorsal forewing in females; (6) rounder wings, particularly in males; (7) not prominently developed areas of dark scales on leg tibiae in most specimens, and (S) arid, desert and rocky slopes habitat. Relationships with other Strymon species are discussed and life history data are presented and illustrated. Hechtia texensis (Bromeliaceae) is established as the larval foodplant in the Big Bend National Park area. Over 40 specimens and live individuals of the new species are illustrated to show the extent of wing pattern variation.