PROTECTIVE RESEMBLANCE, WITH EXAMPLES 101 



The Weevil Bark 

 Imitator 



T first glance at this photo- 

 graphic view of burr-oak 

 bark, one would little sus- 

 pect the presence of an 

 insect resting on it. Yet the 

 weevil shown near the middle of 

 the picture is an actual portrayal 

 of this insect just as I found it.^ 

 This well protected gray weevil 

 is known as Ithycerus. The 

 larvie feed on the tender shoots 

 of the burr-oak, while the adult 

 feeds on the bark of this tree. 

 The gray body of the weevil is 

 dotted with black, and bears 

 longitudinal indented lines, which 

 ^YV'^ ■ ' '.gSffli blend very perfectly with the 

 fl'7''^>^k.'^^^^ uneven or craggy spaces in the 

 rough bark. In the section 

 on tiie Twig Impersonator, I referred to it as a case of special 

 protection. The whole body of the geometrid caterpillar bears 

 a strong resemblance to a twig. In like manner the walking- 

 stick presents the same kind of special resemblance. 



But in the present case of the weevil, the markings and 

 sculpturing on the upper surface of its body are the features 

 most effective in concealment. The most singular thing about 

 this resemblance is the impression of bark-like roughness con- 

 veyed by the weevil's color. Viewed at a distance the beetle 

 is detected with the greatest difficulty. 



One of the most fertile sources of evidence supporting the 

 theory of natural selection was drawn from cases of protective 

 resemblance or what some have termed defensive coloring. 

 Samples are numerous among the insects in nature if only one 



1 At Mill Creek, Illinois, May 30, 1903. 



