142 JOURNAL OF THE 



tain its increased diameter. May it not be that the tnbe Nvhich 

 accommodates the young spider is in this way enlarged to 

 meet the demands of its subsequent growth?* A little later 

 this noiseless, industrious worker came up to repair the other 

 rent, which she did inditferentlv. She was evident! v finish- 

 ing up her "job,'^ and so she proceeded to take down her 

 "scaifoldiug.'^ Here and there the fangs were thrust through the 

 wall of the tube and it was pulled inward and loosened from the 

 wall of the excavation and from the glass, so that, excepting a 

 limited area left adhering to the glass, the tube hung in the exca- 

 vation. Inasmuch as the tube was not straight and was for the 

 most part of nearly equal size with the excavation, it did not 

 dangle, but was in light contact with it at numerous points. 



I do not doubt that the history now given of this tube made 

 in captivity is, with trivial variations, the history of tlie tube in 

 its natural environment. The chief features of this history may 

 be summarized : 



1. The lower part of the aerial portion of the tube attached 

 to the tree for support is the first to be made. 



2. The excavation in the ground keeps but little in advance 

 of the tube manufacture. 



3. The earth from the excavation is brought up through the 

 tube and dumped out through a rent near the upper end.f 



4. The tube is usually placed in a nearly vertical position, 

 any considerable departure from the vertical being made to avoid 

 an obstacle.^ 



*The conclusion that the spider spends lier life in the same tube is not without war- 

 rant. One tube I [lad under observation for two years. In that period it was twice 

 repaired. Having been by some means broken loose from its supporting tree, the fallen 

 tube was not lifted to its place again, but was torn open at the bend on the surface of the 

 ground and a new portion above ground, continuous with the old below, was built upward 

 and fastened to the tree. (Cf. p. 13t;.) That this had been done twice was clear from the 

 occurrence of two old prostrate portions attached to the tube as it stood. I cannot say 

 certainly that it had increased in diameter. It may be mentioned, further, that while 

 digging out a certain tube I discovered at different deptlis near the lower end two very 

 short branches— cut-offs. The upper seemed worn and older than the iowei-. In each 

 were found exuviic of the spider, legs and cheiicerfe. The fangs in the upper cut-off 

 were ;i mm., in the lower 4 mm. So that this spider had dwelt in the same tube during 

 the period between two successive moults, to which time should be added an indefinite 

 period before the first moult and another after the second. (Cf. Blanchard, Pop. Sci. 

 Mon., Vol. 3:i, p. 8(t«.) 



fin the natural situation it i.s usual to see at the side of the tube on the ground a pile 

 of earth evidently from below. In one such pile I found a gravel whose greatest length 

 was 9 mm., and whose greatest width was (i mm. 



JThe subteiranean jtortion of one tube was loosely spiral owing to the presence of two 

 roots in its path, one above the other. I have seen but one tube whose aerial portion 

 attached to the tree was not nearly vertical, and no satisfactory explanation of its excep- 

 tional position has occurred to me. 



