The crescents form a complex group of poorly understood species, partly as a result of the fact that they are often very similar in appearance. Extensive genetic research by Wahlberg et al. (2003) has not clarified the species relationships. The Tawny Crescent is similar to P. tharos and P. cocyta, but has more upperside black markings than cocyta, and the tip of the antennal club is black and white, not not black, white and orange as in cocyta and tharos. This character is not reliable for separating females of these species. Female crescents in general have more black markings on the upperside and paler orange spots in addition to the orange ground colour; and are best identified by association with males from the same population. Our populations are subspecies lakota (Scott 1994).