Wolfson 1938 June 28 (Co.) Microtus richardsoni Tunnel Cr., 15 mi. W Bend, 6100 ft., Deciduous Co. One during the day have caught the mouse in two instances. Are they more diurnal than nocturnal? From stomach contents food seems to be green grass and leaves. Entrance to hole in one instance was en- larged and formed a pocket in the soil. It was "lined" on the bottom with grass and leaves. The runs do not appear to be actively constructed by cutting of grass, but appear to be formed passively due to repeated use and they are not always well defined except in the instances when they were under logs. No good evidence that the mouse takes the rolled oats bait. Traps when not placed in runs, but immediately on them, have failed to catch them. But when placed in runs directly have not failed. From way mice are caught in the traps evidence seems to