210 



AMERICAN SPIDERS AND THEIR SPINNING WORK. 



from 

 Cocoon. 



Arg-iope 

 cophi- 

 naria 

 Cocoons 



the outer envelopes. (Figs. 242, 243.) I have noted these openings in co- 

 coons of Agalena nffivia which were under observation for that purpose; 

 the period at which the openings were cut was identified, and tlie 

 Egress jj^^jg inmates seen peeping out at the round doors, of wliich there 

 were, in some cases, a number opened, from which also they 

 escaped when the cocoon was agitated. Similar openings have 

 frequently been observed in the cocoons of Argiope cophinaria, Epeira 

 cornigera, Argyrodes trigonum, and in numerous examples of Epeiroid, 

 Tubitelarian, and Laterigrade cocoons. In these, however, as a rule, there 

 was only one opening, but sometimes two. 



Professor Wilder has recorded some facts upon this point. ^ Cocoons 

 of the Basket Argiope kept by him in South Carolina were never seen to 

 be pierced by the inmates. Of four hundred and six cocoons 

 obtained on James Island in the spring of 1865, only one hun- 

 dred and thirty-four were entire, presenting no opening what- 

 ever. Of the others one hundred and ninety were pierced when 

 found, but no spiders came out of these before May 10th. The 

 openings in them, were similar to that made in a New York cocoon June 

 14th, by the inmates themselves. This hole was near the pedicle or stem 



of the cocoon, and from it 

 the young escaped. Of the 

 remaining eighty-two co- 

 coons fifty-nine were torn 

 in one or more places, and 

 loose silk proceeded through 

 the rents. Professor Wilder 

 once saw a little l;)ird, about 

 the size of a sparrow, fly 

 at a cocoon hanging in a tree, make one or two quick pulls and then re- 

 treat. He is therefore inclined to think that all the above rents were so 

 caused ; and, as these attacks would usually open the cocoon without in- 

 juring the inmates, he drew the inference that this might be a provision 

 of Nature, somewhat like the fertilization of flowers by insects, by which 

 the invasion of the cocoon should really permit the continuance of the 

 species. 



There may be some ground for this inference, but it is certain that in 

 ordinary cases no such external provision is required. Birds are much 

 disposed to use the silken material of spider cocoonerj' for their 



Fig. 242. Fig. 243. 



Drassid cocoons, to show the openings out of which the young 

 have escaped. 

 Fig. 2-12. Front view. Fig. 243. Side view. 



Delivery 

 by Birds. 



nest building operations. Mr. Thomas Meehan, the botanist, has 

 seen the pewit engaged in collecting spider's spinningwork on his 

 grounds at Germantown. Hunnningbirds are known to make large draughts 

 upon spider webs for nest building material. I have in my collection 



' Proceed. Am. Assoc, 1873, page 2C0. 



