No. 2.] PROTECTIVE RESEMBLANCES IN SPIDERS. 93 



protective industry. They fit with such absolute accuracy into 

 tlie openings of the nests and are so covered on the upper side 

 with moss, earth, hchens, etc., as to he indistinguisliable from 

 the surrounding surface. 



The rectilinear lines which are stretched in front of the 

 webs of many Epeirids are useful in taking and sending on to 

 the spider the shock which tells of an approaching enemy. 

 Some spiders, when danger threatens, shake the web so vio- 

 lently as to grow indistinct to the eye, and others, as Pholcus 

 atlanticus, hang by the legs and whirl the body rapidly with the 

 same bewildering result. 



Mr. Herbert Smith gives me the excellent suggestion that 

 the sideways movement of the Thomisida3, or Laterigradte, has 

 a direct protective value, since the enemies of spiders are accus- 

 tomed to allow for a forward, but not for a lateral movement of 

 their prey. 



A habit common to many spiders, especially among the 

 Epeiridse, is that of dropping to the ground at the approach 

 of danger and resting motionless among the dirt, sticks, 

 leaves, etc., which they resemble in color. The holding of the 

 body in some peculiar position, as in Uloborus, Hyptioides, and 

 the flower-like Thomisidse, is a necessary accompaniment to the 

 color modification. 



The cocoons of spiders are seldom left exposed and unpro- 

 tected. We find them in corners and crevices, concealed in 

 rolled up leaves or under bark. Very often the cocoon itself 

 is covered over with a sheet of web. In some families the 

 mother carries it about with her attached to the underside of the 

 abdomen. In others she carries it in her falces until the young 

 are hatched. The cocoons of others, as Uloborus, Argyrodes, 

 etc., while hung out in the web are still concealed by deceptive 

 form and color, or by being covered with rubbish. 



Cambridge speaks of A. brunnea.wliose cocoons "are covered 

 over very soon after they are made and the eggs deposited in them, 

 with a coating of clay, which effectually destroys all their form 

 and beauty. This coating of clay answers probably two ends : 

 first, the concealment of the cocoon and its protection from 



