LEPIDOPTERA 



219 



Some of the hawk-moths are small or of medium size; but most of 

 them are large. They have the most powerful wings of all Lepidoptera 

 in our fauna. As a rule they fly in the twilight, and have the habit of 

 remaining poised over a flower while extracting the nectar, holding them- 

 selves in this position by a rapid motion of the wings. This attitude 

 and the whir of the vibrating wings give them a strong resemblance to 

 humming-birds, hence they are sometimes called humming-bird moths; but 

 they are more often called hawk-moths, on account of their long, nar- 

 row wings and strong flight. 



Of all the beautifully arrayed Lepidoptera some of the hawk-moths 

 are the most truly elegant. There is a high-bred tailor-made air about 

 their clear-cut wings, their closely fitted scales and their quiet but ex- 

 quisite colors. The harmony of the combined hues of olive and tan, 

 ochre and brown, black and yellow, and grays of every conceivable shade, 

 with touches here and there of rose color, is a perpetual joy to the artistic 

 eye. 



The larv£e of the Sphingidse feed upon leaves of various plants and 



Fig. 377. — Sphinx chersis, larva. 



trees and are often large and quite remarkable in appearance (Fig. 377). 

 The body is cylindrical and naked and usually has a horn on the eighth 

 abdominal segment. Sometimes instead of the horn there is a shiny 

 tubercle or knob. We cannot even guess the use of this horn, unless it is 

 ornamental, for it is never provided with a sting. These caterpillars 

 when resting rear the front end of the body up in the air, curl the head 

 down in the most majestic manner, and remain thus rigid and motionless 

 for hours. When in this attitude they are supposed to resemble the 

 Egyptian Sphinx, and so the typical genus was named Sphinx and the 

 family the Sphingidas. 



Most species pass the pupa state in the ground in simple cells made in 

 the earth; some, however, transform on the surface of the ground in 



