ADAPTIVE COLORATION 



2I 7 



the illuminated and the shaded side of a mid-rib, and the side- 

 veins as well are imitated ; there are even small scattered black 

 spots resembling those made on the leaf by a species of 

 fungus. Furthermore, the butterfly habitually rests, not 

 among green leaves, where it would be conspicuous, but among 



leaves with which it har- 



FIG. 240. 

 monizes in coloration. 



Notwithstanding a recent 

 discussion as to whether 

 it usually rests in pre- 

 cisely the same position 

 as a leaf, this insect cer- 

 tainly deceives experi- 

 enced entomologists and 

 presumably eludes birds 

 and other enemies by 

 means of its deceptive 

 coloration. 



Some of the tropical 

 Ph as mid se counterfeit 

 sticks, green leaves, or 

 dead leaves with minute 

 accuracy. Our common 

 phasmids, Diapheromera 

 femorata and veliei (Fig. 

 240), are well known as 

 " stick insects " ; indeed, 

 it is not necessary to go 

 beyond the temperate zone 

 to find plenty of examples 

 of protective resemblance. Geometrid caterpillars imitate twigs, 

 holding the body stiffly from a branch and frequently reprodu- 

 cing the form and coloration of a twig with striking exactitude ; 

 and the moths of the same family are often colored like the 

 bark against which they spread their wings. Even more per- 

 fectly do the Catocala moths resemble the bark upon which 



Diapheromera veliei, on a twig. Natural size. 



