LEPIDOP 7 ERA . 
331 
which this genus belongs. In the Hawk-moths the frenu 
lum is usually well preserved, but in a few it is wanting or 
rudimentary. In many genera vein III 3 of the fore wings 
coalesces with vein III, to its tip, so that vein III is only 
four-branched. 
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. As a rule they fly in the twilight, 
and have the habit of remaining poised over a flower while 
extracting the nectar, holding themselves in this position by 
a rapid motion of the wings. This attitude and the whir of 
the vibrating wings gives them a strong resemblance to hum¬ 
ming-birds, hence they are sometimes called Humming-bird 
Moths; but they are more often called Hawk-moths, on ac¬ 
count of their long, narrow 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 exquisite 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. They seldom have vivid colors except touches of yel¬ 
low or pink on the abdomen or hind wings, as if their fas¬ 
tidious taste allowed petticoats only of brilliant colors always 
to be worn beneath quiet-toned overdresses. 
The larvae of the Sphingidse feed upon leaves of various 
plants and trees, and are often large and quite remarkable 
in appearance (Fig. 408). The body is cylindrical and 
naked and usually has a horn behind near the end of the 
body 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 of the body up in the air, curl the 
head down in the most majestic manner, and remain thus 
