376 



AMERICAN SPIDEKS AND THEIR SPINNINQWORK. 



friend, who heard this statement, suggested that the spiderlings might be 

 " playing mothei' " and dandling their rag baby cocoons as our children 

 do tlieir dolls ! 



Since the spiderlings thus have the habit, it may perhaps be consid- 

 ered as primarily for personal protection, and it is interesting to find it 

 transferred to the protection of the cocoon. Or, if we suppose that the 

 habit arose primarily to protect the cocoon, it is even more interesting to 

 think that it has been carried over by heredity to tlie young for their 

 own protection. It is impossible not to suspect that this habit may have 

 arisen from the prevalent custom of trussing up newly caught flies for food. 

 In the cases of Cyclosa caudata (Fig. 318) and Cyclosa bifurca (riate 

 IV., Figs. 10 and 11) one must allow a striking resemblance between the 

 general appearance of the cocoons and the mothers 

 who make them. But when one comes to inquire 

 if the like resemblances prevail generally among 

 spiders, he finds that these two species, and a few 

 others, stand in a small group by themselves. As 

 shown in the preceding chapter on Color, there is 

 little resemblance between the great majority of spi- 

 der mothers and the cocoons which they make, 

 either in general shape or color. 



However, it must be remembered that the value 

 of cocoon mimicry would naturally be limited to 

 those species which hang their cocoons in or upon 

 their snares, and to those which brood their cocoons 

 or watch upon or near them while the young are 

 being hatched. Of course, there would be no util- 

 ity in such a resemblance in species that make their 

 cocoons and forthwith abandon them or die. Nev- 

 ertheless, if we glance over the list of mothers that 

 hang their cocoons in their snares, it becomes ap- 

 parent that even with them cocoon mimicry must 

 be limited. Argyrodes trigonum, as she hangs 

 bunched in her retitelarian web (Fig. 109, page 113), might be said to 

 have some resemblance to her basket shaped cocoon. The familiar The- 

 ridium tepidariorum is also a good example of resemblance between a 

 mother and her cocoons, both in general shape and color. (See Chapter V 

 page 112, Fig. 107.) 



Uloborus plumipes is not unlike her cocoons as she hangs with 

 bunched and elongated legs beneath her orb. (See Fig. 104, page 109.) 

 In fact the Peckhams cite this species as an example of deceptive 

 resemblance.! In Wisconsin these observers found Uloborus invariably 



' Observations on Sexual Selection, page 76, pi. iv. 



Piu. 320. Collections of insect 

 debris in the orb of a young 

 Cyclosa caudata. 



