216 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



nous 

 Habit. 



test the effect of a current of air, I slightly raised an adjoining window, 

 admitting a light play of wind across the fence on the column x. In 



three minutes two lines 

 were fastened upon the cap 

 of the puppet, and two spi- 

 ders had begun to cross 

 from the points marked 2, 

 3. These lines were so del- 

 icate that I had not seen 

 them until the motion of 

 the spiders along invisible 



bridges directed particular 

 attention to the spots. 



PIG. 248. Migration instinct. F, fence of netted lines; 1, 2, 3, Within an hour all the 

 points of first departure ; B, bridge lines for transit ; n, final colony but tWO had Crossed 

 assembly of spiderlings. \. 



over the fence (F) to the 



puppet, and were swarmed around the head, face, and chest of the figure, 

 and upon a mass of lines (n) that stretched to a wire (w). A triangular 



bridge of lines (B) had now been formed, whose apex was 

 Grega- j. ne h ea( i o f ^ ne puppet (z), and which broadened out, touching 



the columns (y and x) and connecting with the first perpendic- 



ular bridge (F) by the three principal points (1, 2, 3) from which 

 the migration had proceeded. 



In the course of three days, by arranging various elevated objects over 

 the table, and breaking off the threads that floated beyond the prescribed 

 limits, I had induced the brood to cover a space having a linear boundary 

 of about twelve feet. The greater portion of the area thus bounded be- 

 came at last sheeted by a web composed of the innumerable lines emitted 

 by the little spinners, so that the whole presented a quite good miniature 

 of the canvas tents of a traveling circus company. 



For long periods the little creatures would hang quite still, separated 

 from each other by distances varying from three-fourths of an inch to 

 one, two, and three inches. In these rest- 

 ing moments they hung inverted between 



two lines which they grasped re- 



Position ,- T r, ,1 p 



spectively by the four feet on 

 in Rest. f, J 



either side; the abdomen was 



elevated somewhat, a short thread issued 



from the spinnerets, and was attached to 



an upper line, thus helping to support the F ' G " 



body. (Fig. 249, 1.) Occasionally the two 



hind legs grasped a cross line h'ung upon or above the parallels, and the 



thread from the spinnerets was also attached to the cross line. (Fig. 



249, 2.) 



lSt. 



