566 PROCEEDINGS OF THE ACADEMY OF [Dec, 



young emerge, though she may carry it about within the nest. In 

 no case have I seen the mothers with cocoons taking food before the 

 young hatch; the nest is kept closed through this period, and the 

 spiders pay little attention to insects moving on its outer surface. 

 Geotrecha. 



G. crocota and G. pinnata were not observed to make any nests in 

 confinement, while G. bivittata constructs a very thin, small saccular 

 nest. The conclusion of the cocooning was described by me (1903) 

 for G. (Thargalia) bivittata, and this summer I have seen the act 

 several times in the case of G. pinnata, and as follows: The cocoons 

 are discoidal, excessively flattened and scale-like, their free surface 

 (cover) very tough in consistency and difficult to tear open; under 

 natural conditions they are spun against a stone, while all of the six 

 cocoons made in my glass cages were placed at the junction of the 

 floor and the side ; thus they were circular discs bent in the middle at 

 a right angle. $ 1566 on 22 July began spinning a cocoon-base at 

 7.20 P.M. She spun slowly, sweeping the spinnerets from side to side, 

 over an area of about one and a half times her body length, at the 

 junction of the wall and the floor, so that half the base was horizontal 

 and half vertical. Half an hour later her labor had accomplished a 

 ring of pearly silk, most beautiful to behold, slightly elevated and with 

 almost no silk in the enclosed space. At 8.35 she began spinning 

 rapidly on this central space, then from 8.55-9.45 she was repeatedly 

 interrupted by the males A and B (as previously described) At 

 10.45 she ceased to sweep her spinnerets across the base, and instead 

 raised and lowered them in applying silk near the middle of the disc, 

 at the same time swaying her body backward and forward, thus pro- 

 ducing a central cushion of softer texture. After each spinneret 

 application the abdominal apex was elevated to a height equal to 

 about two-thirds the length of her cephalothorax, then the spinnerets 

 again applied. She ceased this abruptly at 10.57, stood over the 

 centre of the base, discharged from her genital aperture a clear globule 

 of viscid fluid upon it, and in this discharged in succession 8 large 

 yellow eggs, this whole oviposition occupying two and a half minutes. 

 But she attempted in vain to liberate herself from the viscid drop, 

 and began to eat the eggs; this miscarriage may have been due to the 

 late copulation. In the case of another individual ( 9 1572) the work 

 on the cocoon base lasted from 9.45-10.57 P.M., the oviposition for a 

 minute and a half, and the cover-spinning from 11.00 P.M. to after 

 12.45 A.M., when I left for weariness. The first ten minutes of the 

 cover-making were occupied in carrying thread from the edge of the 



