Superfamily Argiopoidea 



and was lemon-yellow in colour except the red band on either 

 side of the abdomen. It was taken in August. 



This spider is remarkable for the change in colour which takes 

 place in it when it migrates to flowers differing in colour from 

 those previously occupied. In the spring and in the early part 

 of the summer it is most often found in the flowers of Trillium. 

 the white fleabane, and 

 other white flowers. Its 

 ground colour is then white, 



Fig. S77- 



PALPUS OF MALE OF 



MISUMENA VATIA 



Fig. 578. 

 MISUMENA VATIA AND EGG-SAC 



which protects it from observation by the flower-visiting 

 insects, and enables it more readily to capture them. Later 

 in the season it migrates in large numbers to the flowers 

 of goldenrod, and is then usually yellow. The spray of golden- 

 rod illustrated by Fig. 579 bore two of these spiders, one be- 

 neath each branch, which resembled the flowers in colour so 

 closely that it was very difficult to detect their presence. 



Doctor Packard ('05) proved experimentally, by placing white 

 individuals on goldenrod that they changed from white to yellow 

 in the course of ten or eleven days. 



Misumena alcatoria (M. a-le-a-to'ri-a).— - This is a common 

 white or yellow crab-spider; the female resembles Misumena 

 valia, described above, quite closely; but it (Fig. 580, a) does 

 nol have the crimson markings at the sides of the abdomen, 

 characteristic of M . vatia though it occasionally has dark reddish 

 brown marks in the same places and a double row of dark spots 



527 



