100. El Cajon Canyon, 3400 ft. E. base San Pedro Martin Mts. Lower California, Mexico. June 2. Gilmore 1946. The Homomys caught last night in one of the three or four fresh workings around here. All are situated up the canyons at a slightly higher altitude and all are located in wet sand at the edge of the stream. There were about 20 dirt piles in a group along the stream where this one was caught and since it was the only one caught out of the 5 traps set there and since no more were caught there during today, it seems probable that it was responsible for all the digging. The Phymopus lateralis are becoming much more common, both adults and young. The Mimus polyglottus leucopterus and Bemidura macroura margarella are also increasing and one can often hear the singing of the former where at first none were heard. The trapping is poor which together with an abundance of voracious ants and bad luck in have quite a number of the catches caught by the skull, makes the total number of good specimens quite small and insignificant.