72 Miscellaneous. 



• one of these tentative lines. The confused network of circumjacent 

 lines was gathered together in a little flossy ball at the point of 

 union, which was now made the centre of the orb, the first drop- 

 line and the two divisions of the cross-line constituting the three 

 original radii. From there the spider proceeded to lay in the radii 

 and complete the orb. The speaker described this process in full, 

 as illustrated by the industry of this and other individuals. The 

 time occupied in constructing the orb proper was half an hour, 

 while the work of prospecting for and obtaining a foundation con- 

 sumed more than an hour. Even then the orb was very irregular, 

 and showed decided traces of the want of the usual well and 

 orderly laid foundations. An examination of a number of web-sites 

 which had been marked upon the same grounds showed that, in 

 every case where the surroundings had allowed an easy and good 

 entanglement by the wind, the spider had made webs at an earlj' 

 hour, and with straight and regular foundations. 



Dr. McCook concluded that the above observations, although not 

 wholly conclusive in themselves, were sufficient warrant for the be- 

 lief that air-currents have a large part in placing the original frame- 

 work or foundation-lines of orb-webs, and that spiders habitually 

 make use of them for that purpose. He doubted, however, whether 

 there was any thing like a deliberate purjiose to connect the point of 

 occupancy with any special opposite point. It seemed to him that 

 the spider acted in the matter very much at haphazard, but with a 

 general instinct of the fact that such behaviour would somewhere 

 secure available attachments. Many of her bridge-lines were evi- 

 dently tentative and were chiefly at the mercy of the breeze, although 

 some observations seemed to indicate a limited control of the thread 

 by manipulation. 



He added that on previous occasions he had actually observed the 

 laying in, by air-currents, of lines which were immediately used for 

 foundations. The above studies had l)een undertaken simply to 

 verify such studies, and because he had retained but the briefest 

 notes of former observations. While this use of air-currents is cer- 

 tainly placed beyond doubt, it is as cei'tainly not the only mode of 

 laying foundation-lines, and is dependent very much upon the site 

 chosen, the condition of the wind, the abundance of prey, &c. Webs 

 built in large open spaces are perhaps always laid out by bridge- 

 lines ; in more contracted sites the frame-lines are generally carried 

 around, and often a foundation is the result of both methods*. — 

 PrOG. Acad. Nat. Sci. PhilacL, Oct. 4, 1881. 



* Since these notes were communicated, a copy of ' Nature ' (Sept. 22, 

 1881) has been received, in which it is said tliat Mr. Cambridge, in the 

 second volume of his 'Spiders of Dorset,' modifies the opinion above 

 quoted concerning the influence of air-currents. I have not yet received 

 that volume, but make this statement on the authoritv of the journal 

 referred to.— II. C. McC. 



