110 PROCEEDINGS OF THE ACADEMY OF [Jan., 



certain web lines around the cocoon, and fastened new supporting 

 lines to it. 



9 No. 154, after making 3 normal cocoons, all suspended in her web, 

 made a mistake in the construction of her fourth one. On July 24, at 

 8.13 A.M., I found her finishing the base (flviffy ball) of the fourth 

 cocoon; but owing to some accident this was not a rounded mass of 

 silk, but a hollow cone hung from its apex by a thick thread ; the form 

 had probably become changed by her weight upon it. From 8.20 

 until 8.23 she clung to this base, pressing her epigynum several times 

 against its lower opening, and from 8.23 to 8.24 she oviposited upon 

 it. But her weight upon the silken base had gradually unraveled the 

 latter, so that it becoming pulled out, the egg mass sank with it to 

 the floor, where all adhered to some dead flies. From 8.24 until 8.40 

 she made several ineffectual attempts to raise it into the web, then she 

 left it and went to cocoon No. 3, spun a cap of silk first around its lower 

 surface, then upon its sides, then kneaded this new covering with her 

 palpal tips. Evidently she had the impression that she was finishing 

 the cocoon already begun, and seemed to have forgotten the neglected 

 egg mass. At 10.05 she returned to the latter and fed on the eggs, 

 probably confusing them with the dead flies to which they adhered ; at 

 10.10 she pulled excitedly at the neglected base, as if trying to raise it, 

 for 6 minutes, but then left it on the floor and did not return to it again. 

 Thus she had not been able to rectify the misshapen base of the cocoon, 

 and under the impulse to make a covering had made this covering 

 around an already finished cocoon. 



In all these cocoonings, then, a base of a spherical mass of loosel}' 

 curled silk is first formed, the ova (included within a viscid drop of 

 fluid) deposited upon its lower side, then the whole covered with silk, 

 finally this covering kneaded mth the ends of the palpi. The reason 

 why the external surface of the cocoon is brown in color I cannot say ; 

 possibly the silk secreted last maybe different chemically — i.e., proceed 

 from different spinning tubes. In one case a complete cocoon was 

 made without oviposition. 



A succession of cocoons are formed by the same individual, the num- 

 ber of those made by my captives with the dates of th(:ir construction 

 being as follows : 



(1) $ No. 6: May 19 (the ova did not develop). 



(2) 9 No. 16 : May 25 (hatched June 28) ; June 14 (hatched) ; July 7 

 (eggs did not develop); July 14 (eggs did not develop); July 24 

 (hatched); July 31 (only a few of the eggs hatched); August 21 

 (hatched). 7 cocoons in all. 



