-8 9 - 



ion, is followed by a majority of those observed, and seems to indicate a 



natural instinct, a more potent influence of inherited habit in some, while 

 in others the instinct seems to be latent at first and gradually unfolds 

 with the dawning of consciousness! According to the normal type, the 

 spider takes up pellets of earth with its mandible, and turning around 

 places them upon the soil by the side of the tube, which is being dug; 

 or carries or throws them to a short distance. Occasionally with its 

 spinerets it applies viscid liquid to the pellets and edge of the tube, much 

 as an artificer would alternately place cement and bricks in the construct- 

 ion of a column. The trap-door is built in the same manner, by be- 

 ginning, at one side of the edge of the hole, a horizontal wall to which 

 particles are cemented and pressed in shape to make a Hat, circular, lid 

 to the tube.* 



By a study ol Plate IV we shall see some of the variations from the 

 n irmal types. Fig. i, a, represents one of the spiders, natural size, //, 

 section ol a nest built after the normal type, door represented open, also 

 natural size. All of the other figures, except 15 and 16, are magnified. 

 In fig. 2, one side of tube, a, is extended above ground and carried over 

 the tube. The door, represented open, is hinged at b; when closed it 

 slopes downwards from the hinge attachment, fig. 3. This was the work 

 ol Xo. 3. f!ie arched wall from a, was pressed in shape in the same 

 way that the trap door is, so that when the spider began it at a, I thought 

 it had begun the trap-door, and made this entry in my notes. "At 4.30 

 door begun; two-thirds of the edge used for attachment of the hinge, 

 making an awkward door." When the hinge was made \\i b, it was easy 

 to see the arching of the wall was intentional. In fig. 10, the tube is curv- 

 ed above ground in a similar way,- but the hinge is at one of the sloping 

 sides, making a door that swings to the right and left instead of up and 

 down. This was made by No. 25. Figures 4, 5, 6 and 7 represent the 

 work of No. 15. A trench was dug, using the excavated earth for a wall 

 on each side; the walls were then united by an arch over the middle, one 

 end closed and a trap-door made at the other end. Fig. 8, represents 

 the nest of No. 22, built in the same way as that of No. 15, except that 

 at </, the hole was not entirely closed. No. 13 built what is shown in 

 fig. 9. A trench with a wall each side was first built; in the middle of 

 the trench was dug the tube and the door hinged at the base of one wall 

 .it a, with the distal part of the door elevated at b. Fig. 11, shows the 

 work of No. 24: a trench was dug by the side of the glass with 

 a wall on one side at a; on the other side earth was carried upon the side 



* For description and illustration of the building <>l a nest ami trap-door by this 

 -. see Amer. Nat. for July 1886. 



