Dr. Zweifel 1953 *Pterodyla fodena* 9 mi. N Mazatlan, 100', Sinaloa, Mexico July 12, One found on the road during a slight rain in the evening. 2501-2505 #2 July 13 During the evening, several taken on the dirt road near our camp. They were also abundant on the paved highway. Some were calling from roadside pools. July 16 These frogs seem to be quite terrestrial. We have found Diadema, Smilisia and Agalychnis in trees at night, but none of the dozens of Pterodyla was off the ground. Collecting in the daytime, Beer found one in a hole in the ground, blocking the entrance with its bony head. 6.3 mi. N Ciudad Orogan, Sonora, Mexico July 19 Calling from a small bush a few inches off the ground at the edge of a rain pool in the evening. Escaped. 11 mi NW Vicam, Sonora, Mexico Mixed chorus of Pterodyla and Bufo debilis in a rain pool.