146 NATURE SKETCHES IN TEMPERATE AMERICA 



from two to two and a haK inches in length. Besides the green 

 ground color on the upper part of the body, it is adorned with 

 rows of blue dots; the yellow, eye-Uke spots on the third segment 

 have black centres with a blue streak; the yellow band across 

 the fourth segment which might be mistaken for a mouth is 

 shaded with black behind. The head and under surface of 

 the body and legs are pink. It resembles the troilus caterpillar 

 in form. The food plants upon which it subsists include quite 

 a variety, such as the wild cherry, apple, alder, tuUp tree, 

 black ash, oak, lime, birch, sassafras, and magnolia. Its 

 polyphagous habits may have aided its distribution which 

 extends over the eastern portion of North America, from 

 northern Canada to the Carolinas. 



The green caterpillar of the tiger swallow-tail, shown in the 

 initial photographic illustration, was found in the forest under- 

 growth skirting the bank of a river in June. It was a full- 

 grown example, about two inches in length. As a glance at 

 the picture will show, it is one of the most grotesque forms of 

 caterpillars commonly met with. It had spun a glistening 

 silken web in an exposed situation across a wild cherry leaf, 

 and on these meshes had suspended itself with its back turned 

 toward me. When I recall the first sight of this larva, the im- 

 pression gained of it was a most curious one. The forward 

 mask-like face was remarkably startling. This mask, bearing 

 eye-like spots and the light transverse ridge, gave it an aspect 

 which might easily be mistaken for real eyes and a mouth. 

 This contrivance is only a false face in no way connected with 

 the real eyes and mouth. One might imagine the shock that 

 a bird, or other predaceous enemy, would experience when 

 looking upon this grinning mask. This is in reality the effect 

 produced, for I have seen small birds so alarmed that they 

 lost their appetite and curiosity for these larvse after a brief 

 glance at them. It is certain that these singular markings 

 have the effect of terrifying their bird enemies. 



To really understand the meaning of these extraordinary 

 forms of caterpillars one must go farther back than the fore- 

 going observations. Some additional light on this subject 

 may be gained by a study of the tropical species in 

 their original environment. From the tropical species our 



