THE 



AMERICAN NATURALIST 



Vol. XLII November, 1908 No. 503 



FURTHER STUDIES ON THE ACTIVITIES OF 

 ARANEADS 1 



PROFESSOR THOS. H. MONTGOMERY, JR. 

 University of Pennsylvania 



1. Age Differences in the Snakes of two Argiopids 



To the best of my knowledge there has been made no 

 comparison of the snares of immature and adult spiders, 

 with regard to the problem of whether such snares be- 

 come more complex as the animal grows older. Yet this 

 is an interesting question in its bearings upon the per- 

 fection of an activity through repented effort. 



During the past months of July and August I have 

 studied this matter on two common species of argiopids, 

 Epeira sclopetaria (Clerck) and E. marmorea (Clerck), 

 both of which construct large vertical, orbicular snares 

 that are very favorable for measurements and the archi- 

 tecture of which has been well described by McCook. 2 



My observations were made at Woods Hole, Mass., 

 where there was a large colony of sclopetaria in the labor- 

 atory buildings and beneath the boat wharves, and an- 

 other of marmorea in a marshy woodland. All the webs 

 measured were those in the free and natural conditions, 

 except those of the newly hatched ; to obtain the latter I 

 kept cocoons until they hatched, then freed the young 

 upon the window panes of my room where they spun 

 their first snares. Sclopetaria makes cocoons throughout 

 1 Contributions from the Zoological Laboratory of the University of 



