This adult male beetle was found on the grounds of the hotel at the Cola del Caballo resort, south of Monterrey, Nuevo Leon, Mexico. Image scanned from 35mm slide. I hope someone can check the species ID for me. I keyed this out from the online keys here: http://museum.unl.edu/research/entomology/Guide/Scarabaeoidea/Scarabaeidae/Dynastinae/Dynastinae-Tribes/Dynastini/Dynastes/D-hyllus/Dhyllus.html