140 MOTHS AND BUTTERFLIES. 
horn is to be found only in the young caterpillars, an eye-like tuber- 
cle taking its place in the more mature larva. That this horn is of 
any use to the caterpillar I have yet to learn. It may be the sur- 
vival from its ancestors of a sting; but if such is the case it has 
entirely lost its value as a weapon of defence. The transformations 
usually take place a few inches beneath the surface of the ground. 
A few species make rude cocoons by drawing about themselves 
leaves and twigs on the ground under their food plant, and fastening 
Pupze of Sphinx Moths. 
them together with a few silken threads. They usually pass the 
winter in a pupa state. The chrysalis in some species is furnished 
with a long tongue-case which stands out from the body and is often 
compared to the handle of a jug. 
Among the clear-wing sphinxes, our most common species is 
Hemaris thysbe. In this insect the wings expand about two inches 
and are transparent, the veins and margins being reddish-brown. 
The head and thorax are olive-green; the upper part of the abdomen 
is crossed by a broad band of buff, while the lower part is rich red- 
dish-brown or maroon, and reddish-brown beneath. The fan-like tail 
is black on the sides, with a yellowish-brown central tuft of hairs. 
The under side of the thorax and legs of the insect are light yellow. 
This insect is sometimes very common in June and July, and may 
be seen on hot summer days hovering over the flowers of the garden 
extracting their nectar. It looks not unlike a humming-bird in 
miniature while on the wing. The blue blossoms of the pickerel weed, 
which grows so plentifully along the margins of most ponds and 
