Buckmoth or Sheepmoth

I did some more research. What you have here is a currently unplaceable species near to Hemileuca mania. Lemaire (2002) mentions that the "population [of Hemileuca near mania] from Chiapas, San Cristóbal de las Casas, which is tentatively associated with Hemileuca mania, is characterized by the much darker brown color of the male for wing, slightly brownish tinge of the hindwing..." Lemaire goes on to mention that the females from this Chiapas population do not differ from topotypical H. mania, nor are there differences in the genitalia of either sex. He says there is too much uncertainty to officially name this entity. So, this specimen represents a taxon near Hemileuca mania, which may be a distinct, unnamed species. The male you have photographed is an excellent match for the males figured in Lemaire from near the same locality. I will mention these to Bill Oehlke along with the female Coloradia casanovai.

Not Hemileuca tricolor which is found farther north and has different coloration, particularly a curved AM line on the forewing. The AM and PM lines on this individual are nearly parallel and quite far apart (ruling out most species of the H. tricolor complex in Mexico). This may be H. mania. I will investigate this further.