THE SPIDER AND ITS ALLIES 91 



to which they have been put is in making silk cloth. The 

 silk of the spider is smoother and glossier than that of the 

 silk-worm, but it is much harder to collect in quantity. 

 A spool is passed against the spinnerets of an individual 

 spider and slowly revolved, winding the silk upon it. 

 The difficulty comes in rearing the spiders, for they are 

 extremely voracious and if the supply of flies is insufficient 



FIG. 89. Lycosa,a running spider. FIG. ( JO. Attus, a jumping spider. 

 Ocelli formula below. From Emer- From Emerton. 



ton. 



they attack and devour one another. Consequently they 

 must be kept isolated and fed individually, and yet yield 

 in the end only an ounce or so (about 30 grammes) of 

 silk. Other uses of spiders' silk are : in the construction 

 of cross-hairs in telescopes, and in medicine as a narcotic 

 in case of fevers, a temporary fad. 



Poisonous Spiders. Spiders are feared by many people 

 from a belief that they are very poisonous, even fatally so. 

 Spiders have, indeed, biting jaws provided with poison- 



