We examined several aspects of the biology of Procinura aemula, including diet, sexual dimorphism, and clutch size, from Chínipas, Chihuahua, Mexico. Diet of P. aemula was composed entirely of invertebrates. Orthopterans and crickets were the majority of the diet, both numerically and volumetrically. Prey size was significantly related to snake size (snout–vent length, head size). There was no sexual dimorphism in snout–vent length or head size. Mean clutch size was 4.6 eggs. Clutch size tended to increase with snout–vent length of females, but the trend was not statistically significant.