COCOON LIFE AND BABYHOOD. 



211 



several nests built by a Vireo, the white eyed Vireo probably (Vireo novo- 

 boracensis), which are largely composed of the thick sheetings taken ap- 

 parently from the cocoons of various Orhwcavers and the Speckled Agalena, 

 which may all have been abandoned cocoons. However, it is extremely 

 probable that some of them were filled with young spiders when seized. 

 Such seizure would not necessarily prove fatal to the young, as I have 

 demonstrated by experiment, substituting my fingers for the bill of a bird. 



At the first pull, or as soon as a fracture had been made, a number of 

 the wee fellows would run from the cocoon hurry-skurry and take refuge 

 under surrounding objects. When a pinch or two more had widened the 

 fracture so as to allow the brood to escape freely, and the hand was swung 

 upward through the air as nearly as might be after the manner of the 

 supposed robber bird, a long trail of young spiders floated behind, all 

 hanging on as for dear life to the filaments that streamed backward like 

 a kite tail, and which were the united threads of the whole evicted ten- 

 antry forced into the utmost activity of tlieir spinning organs. 



Nearest to the fingers tlie filaments were thickly placed, and here the 

 young balloonists were massed. Further on they were less in number, and 

 so to the end of 

 this curious pennant, 

 where one or two 

 clung to the taper- 

 ing point of gossa- 

 mer. Of course, dui*- 

 ing the rapid motion 

 some of the spider- 

 lings were detached 

 from the mass and 

 floated away upon 

 single or manifold 

 strands. It is thus easy to see that a bird carrying a torn cocoon under 

 similar circumstances might distribute a large portion of a brood along 

 the course of her flight without destroying many. Even for those re- 

 maining within the cocoon or clinging to the shreds thereof, there would 

 be good chance to escape scot free after the work of weaving the silken 

 material into the nest should begin. The action of birds in opening 

 cocoons is an accident of which spiderlings doubtless avail themselves, but 

 it probably goes for little or nothing in the natural delivery of the brood; 

 and the peculiar spinning habit of spiders tends to protect them from the 

 violence of such attacks when made. 



Mrs. Mary Treat has informed me that the young of Argiope cophi- 

 naria have been observed by her escaping through the pedicle or stem 

 of the outer cocoon case. A reference to tlie figures of the cocoons of 

 this species in Chapter V. will show how this is done. The pedicle of 



Fig. 244. Young Agalenas escaping from a plundered cocoon. 



