COCOON LIFE AND IJAllVirooh. 209 



about half way removed from the abdomen. Tho foot pushed downward, 

 and at the same time the abdomen appeared to be pulled upward, until 

 the white poucli was gradually worked off. (Fig. 241.) The motion mu 

 not unlike that of a child stripping off its night dress by pushing it down 

 the body and stepping out from the drapery. 



Life within the cocoon is not wholly destitute of "moving acei.lmts" 

 and "hairbreadth 'scapes," if we may believe Professor Wilder, who ar- 

 gues that the young of Argiope cophinaria eat one another while 

 Cocoon y et w Jthin cocoon limits. His reason is that a comparison of 

 baMsm ^ ie contents ^ cocoons opened early in the season with those 

 opened later showed that the spiderlings were fewer in nnmhi-r 

 but larger in size. 1 He infers the same thing from the fact that after 

 egress the young do prey upon one another, but without sufficient ground, 

 as the one fact by no means implies the other. My own observation has 

 been, of all species, that the young live together peacefully while within 

 the cocoon. However, I have chiefly studied the cocoonery of our more 

 northern latitudes. 



In southern latitudes, where the hatching probably occurs earlier with 

 some species, and the period of confinement after hatching is thus much 

 prolonged, or the appetite of the young quickened by the climate, hunger 

 may assert its supremacy. Yet, even in the case of some southern spiders, 

 as examples of Zilla from southern California, reared during winter in my 

 study under conditions of temperature not very different from their native 

 latitude, there never appeared a trace of cannibalism until after the young 

 araneads had woven their first independent snares. In the case of most, 

 probably of all, species in our more northern climate, during the greater part 

 of the four months intervening between hatching and egress, the young 

 are probably more or less torpid by reason of the cold, and thus with 

 natural appetite still in abeyance. Even in our Southern States the influ- 

 ence of season is seen by a general suspension of activity in the insect 

 and araiiead world ; and, independent of climatic influence, Nature doubt- 

 less gives a semidormant tone to the spider young. 



Whatever may be the truth as to Argiope and Nephila, I am certain 

 that many species do not have this cannibal habit within the cocoon, nor, 

 indeed, for some time after egress therefrom. Mr. Pollock's observations' 2 

 of Argiope aurelia, of Madeira, quite correspond with this statement, for 

 the broods were always friendly within the cocoon, and indeed for a fort- 

 night after leaving it. 



III. 



The spiderlings themselves procure exit from the cocoon in most spe- 

 cies. This is frequently accomplished by cutting a small opening through 



1 Proceed. Am. Asso., VII., 1873, page 200. 2 Ann. and Mug. Nat Hist.. lsn.\ page 460. 



