Many individuals may be found in a certain vicinity. In the valleys where oak and sycamore trees grow abundantly there can be found as many as seventy-five on the lower trunk of one tree. They are all of one or two species. In all the student collections that have been carried on here in college for the last ten years there have never been more than four or five species collected. It was only through special collection that the other species were found. Very few were found under stones, where they are so often spoken of as living, and few were found among fallen leaves. Some were collected in rotten poplar and pine logs. In the marshy ground at Chino they were found under leaves and stones and were very abundant on the poplar trees. The distribution of the pseudoscorpions extends from an altitude of 5000 down to within ten feet of the ocean. Concerning their habits of living little can be found. Many small spiders were found in their claws, also the small mites that live underneath the bark of trees. Several experiments were tried with some that were brought into the laboratory. The results were: 1. The pseudoscorpions would not go into Eucalyptus bark. 2. They could not live in a glass dish if water was not placed in it somewhere. If water was left out, they would dry up within twenty-four hours. 3. They avoided the sunlight and would go under cover. 4. They would remain in one spot without moving for a day at a time. _Chelifer cancroides_ Linn _Description_: Length--including mandibles, 3 mm.; pedipalps, 4 mm.; claw, 1.5 mm. Color--Pedipalps, dark reddish brown; cephalothorax, dark reddish brown; abdomen, lighter than the palps and cephalothorax; legs, light yellow brown. _Cephalothorax_: Evenly rounded in front; one distinct median suture, two distinct eye spots. _Abdomen_: Twice as long as it is broad and divided into eleven distinct sutures. All of the scuta about the same size except the last one, which is a great deal shorter and broader than the rest. Each scutum is provided with two strong, spiny hairs on the outer edge. The whole body is heavily granulated, the cephalothorax having knob-like protuberances all along the edges. _Pedipalps_: Larger than the whole animal. Coxa, smooth; trochanter with large protuberance ending in a heavy spine on the outer edge. Femur longer than cephalothorax, pedicellate. Tibia, concave on inner edge, pedicellate, shorter than femur. Trochanter, femur and tibia strongly granulated and sparsely covered with almost clavate hairs. Claw of good size, finger a little shorter than the hand. Hand evenly convex on outer and inner edges. Finger slightly curved, smooth, with many long simple tactile hairs. _Mandibles_: Small, fixed finger provided with many small teeth. Serrula attached throughout length of moveable finger. Spinnerets long and transparent. Mandibles are provided with five or more heavy long hairs. _Flagellum_: Divided into four separate parts.