CONSTRUCTION OF AN ORBWEB. 



69 



from one tree to another, or would fly in the air, he first lets himself down 

 from the twig he stands on by a web as in Fig. 1, and then, laying hold 

 of it with his fore feet, and bearing himself by that, puts out a web as in 

 Fig. 2, which is drawn out of his tail with infinite ease in the gentle 

 moving air, to what length the spider pleases, and 

 if the farther end luippens to catch by a shrub 

 or the branch of a tree, the spider immediately 

 feels it, and fixes the hither end of it to the web 

 by which he lets himself down, and goes over by 

 that web which he put out of his tail as iu Fig. 

 3, and this my eyes have innumerable times made 

 me sure of."i (See Fig. 65.) The habit indeed 

 prevails and is utilized for many func- 

 Use of tions ; sometimes to secure a convenient 

 ■winging jj^jj(.y^g Jqp cleansing the limbs and ab- 

 domen; sometimes as a position of guard 

 or rest when the spider through fright has cast 

 itself from its snare or nest, and has paused mid- 

 way of the ground ; sometimes as a favorable point 

 of departure on a ballooning excursion. But most frequently the swinging 

 basket serves, as here, when exploiting surroundings for an available orb 

 site, and to work in the prime foundation line. While suspended thus she 

 keeps one, or yet more frequently both fore legs extended slightly curved 

 in the attitude of "on guard," and either held rigidly or occasionally waved 



to and fro feeling for the indi- 



FiG. 65. Jonathan Edwards' illus- 

 tration. 



cations of the presence of the 

 friendly trial line, or of un- 

 friendly objects. 



This use of the fore legs is 



habitual in all movements of 



spiders from point to 



''® point. While engaged 



Legs as . , . r j 



Antennae. "^ ^^I'^gging ^ ^ounda- 

 tion line around vines 

 and twigs, over leaves or other 

 surfaces, she will often pause and 

 wave the extended fore legs as 

 though prospecting her way not 

 only, but testing the safety of 

 her surroundings. The action frequently reminded me of the character- 

 istic use of the antennae by ants and other insects; and, indeed, I have 

 little doubt the fore legs of spiders do have in part the function of an- 

 tennae. (See Fig. 66.) 



' Am. Jour. Soi. and Arts, Vol. XXI., 1832, pages 112, 113. 



Fig. 66. Antennal use of the fore legs. 



