Onychomys leucogaster July 20 2½ mi. SW Irrigon, 300 ft., Morrow Co., Oregon Caught my first specimen of this genus in the trap line I had set chiefly for Dipodomys and Perognathus in the plain country south of the Columbia river covered with Purshia and cheat grass, with little close water supply. One specimen of Perognathus parvus in a trap about 35 feet away from where the Onychomys was caught, was de-viscerated and even a small part of the base of the brain eaten.