THE LIFE OF THE SPIDER 49 



ciated with bleeding prey and the taste of the blood prompts the 

 creature. 



If a leg is lost by an immature spider, it is replaced by a smaller, 

 imperfect replica at the next molt, provided a sufficient time has 

 elapsed between the loss and the molt. The regenerated appendage 

 increases in size with successive molts but never quite attains the 

 full perfection of the normal appendage. The same leg can be 

 regenerated repeatedly, so long as the spider is still immature, but 

 at least three successive molts are necessary to attain a size com- 

 parable to that of the normal appendage. 



The regeneration of a leg takes a definite course. A good illus- 

 tration is the crab spider, Misumena calycina. The females of this 

 species have white legs, and when one is lost, the appendage that 

 replaces it is shorter, unmarked (as is to be expected), and deficient 

 in the number of spines, as compared with the normal appendages. 

 In the male, however, the first two pairs of legs are banded after 

 the third or fourth molt, and in each successive molt the amount 

 of pigment in the dark annulae increases. If the male loses a leg 

 during the third instar, when it is still white, after the next molt 

 the regenerated leg is wholly white, but the normal front legs 

 continue to increase their annular pigmental areas. After the fourth 

 molt, the regenerated leg becomes annulate, but the depth of the 

 chromation is much less than in the normal leg. In other words, in 

 Misumena calycina a regenerated leg takes on the normal coloration 

 of the leg at the previous instar, and never quite approximates the 

 normal leg in size and color. 



LONGEVITY 



Most spiders that inhabit the temperate zones live only one year. 

 The yearly population may be divided very roughly into two 

 faunas, one identified with the spring and the second with the fall. 

 Over-wintered or recently matured males of many vagrant spiders 

 are abundant in early spring and are on hand when their females 

 become mature. The crab spiders are found on the ground, in the 

 corollas of spring flowers, or running over the stems of shrubs and 

 the bark of trees. The grassland teems with jumping spiders, wolf 

 spiders, clubionids, and many other wandering types. The sedentary 

 web spinners are likewise well represented by many species that 

 spin inconspicuous orb webs or tangled webs on the vegetation. In 



