378 



PROCEEDINGS OF THE ACADEMY OF 



[1887. 



on the mound about ten inches distant and moved slowly towards 

 the insect, creeping, crouching, evidently directed by the agitated 

 web. It was very tardy in its approach and my attention was 

 unavoidably diverted, but shortly afterward I saw the spider 

 devouring the locust. The question was raised, does the tarantula 

 in natural site take its prey in this way, by lines spread before its 

 den or elsewhere upon the surface of the ground ? Mr. Bates 

 appears to have the ojjinion that the web of the large Brazilian 

 tarantula is used to capture prey; at least, he speaks of birds 

 entangled therein and fed upon by the spider.^ 



The thick texture of the sheeted web is produced by the act of 

 beating downward with the long spinnerets, repeated motions of 

 which up and down make little loops which thicken over the surface 

 and are beaten down and then smoothed over by the spinnerets. 

 (Fig. 3.) The action does not greatly differ from that of all other 



Fig. 3. Spinning the rug; use of the long spinnerets, 

 spiders while engaged upon similar spinning work. In the act of 

 spinning, tarantula frequently reaches one hind claw to the spin- 

 nerets and makes a series of rapid strokes, then stretches out the 

 foot as though carrying the thread with it. It would appear to be 

 intended thus to draw out the silk from the spinning tubes, but the 

 motion was so rapid that I never could exactly make out its full 

 purpose or determine whether it might not be a mode of clearing 



1 The Naturalist on the Amazon, ii, p. 58. 



