PLATE 60. Caterpillar of the moth L'afoca/a ain t itri.\', on a poplar twi.u. 



a. Indicates its head. b. Its posterior end. The bark of the young twigs of this tree is of a 

 peculiar purplish gray color. The caterpillar not only imitates this color to perfection, but it also 

 has the habit of so flattening itself against the twig as to appear a part of the twig itself. This 

 caterpillar on a leafy spray, while alive, was handed at different times to four biologists with the 

 remark, " Isn't that a fine example of protection ? " and none of them saw the caterpillar. 



