n 4 AMERICAN SPIDERS 



they are active during the evening and at night, but they rarely 

 leave their burrows. At the exit of its tube, holding the door ajar, 

 sits the spider, ever watchful for the approach of food. On occa- 

 sion it will rush forth to capture an insect, but most of its prey 

 is taken without completely leaving the burrow. Inside the nest it 

 is an agile creature; outside, a clumsy one. When disturbed, it 

 closes the door firmly and holds the lid with chelicerae and claws, 

 bracing its legs against the sides of the silken burrow. In this posi- 

 tion, considerable force is necessary to dislodge it. Even with the 

 aid of a knife blade one has difficulty in forcing the door. 



Two well-known genera, Actinoxia of the western and Myr- 

 mekiaphila of the southeastern United States, make the type of 

 nest Moggridge called "the double-door branched nest." The trap 

 door of this nest is of the wafer variety. It is a thin, suborbicular 

 cover almost wholly made up of silk, without layers of earth, and 

 lies on the entrance rather than fitting into the aperture. It is not 

 substantial enough to serve as an impregnable barrier to an intruder, 

 being soft and pliable, and not heavy enough to fall over the open- 

 ing if it is pushed back very far. It is only a superficial, hinged 

 cover, which is camouflaged outside with moss, earth, or debris. 

 The burrow proper is a cylinder lined with silk; but the particular 

 innovation in this nest is the second burrow, a secret side chamber 

 cleverly concealed by a trap door so constructed that it can close 

 either the main tunnel or the side branch. (See Text Fig. 3, B.) 



The burrows of Alyrmekiaphila torreya are found on the leaf- 

 mold-covered slopes of Torreya Ravine in Liberty County, Florida. 

 This species digs a burrow that averages about ten inches deep. 

 The nests are usually found in sandy soil penetrated by a maze of 

 roots, and almost always contain at least one or more abrupt bends. 

 Halfway down the tubes are the side chambers, one to a burrow, 

 marked by wafer-type doors. The entrances to the outer burrows 

 are lined with silk, and provided with a peculiar type of door, 

 which, when standing open, is more like a silken collar than a trap 

 door, but which takes on the appearance of a well-camouflaged 

 trap door of the wafer type when closed by a slight push. This 

 door the spiders sometimes leave standing open during both night 

 and day. 



Most of the tarantulas that make an inner door are about two 

 thirds of an inch in length. Their bodies (Plate XIV, male) are 

 slimmer than that of Pachylomerus, ordinarily yellowish brown, and 

 sparsely clothed with brown hairs. Their legs are longer and they 



