136 



Journal of Comparative Neurology. 



ly lived in the nest at the base of the stamens, Fig. 2, B. It is 

 not likely that these spiders had ever before encountered the 

 JropcEolum but both succeeded in availing themselves of the 

 opportunity with great skill. See article by Mr. Turner above. 



Fig. 2. 

 A second instance of adaptive modification of spider habits 

 was also observed by Mrs. Herrick. The polished mirror of the 

 sideboard in our dining-room was found decorated with lace-like 

 tracery of extreme delicacy. The pattern of this fabric was narrow 

 and formed several bands which extended in an obliquely perpen- 

 dicular direction Close scrutiny showed that these patterns were 

 veritable spider-ladders by means of which the upper and lower 

 parts of the frame were placed in ready communication. The spider 

 was not seen but, from the way in which the ladder was arranged 

 in a zig zag line, taut in one direction and loose in the other and 

 attached only at the angles, it was inferred that it was con- 

 structed while laboriously climbing or descending by reaching as 

 far as possible with the hind leg on one side and attaching by 

 an adhesive loop, then with the foot of the opposite side in the 

 same way. The plate glass is highly polished and the web 

 seemed to adhere with difficulty as indicated by "dropped 

 stitches" here and there and irregular deviations in the path. 

 There were five such tracks, of which two crossed others in their 

 course, each 4 — 5 millimeters wide and about 40 centimeters long, 

 crossing the glass. The spider seemed to live in a crevice 

 above the mirror and required to cross the surface often. A 

 loose thread hung from the frame above to the shelf below and 

 seemed a more expeditions ferry. The instance is mentioned in 

 the hope that other observations may be forthcoming. It is pos- 

 sible that the tracery was intended for the attachment of a web. 



