222 NORTH AMERICAN INSECTS. 
1. Libellula, with a flat, short body (Fig. 57). 
2. shna, with a round, cylindrical body (Fig. 58). 
3. Agrion, with a small body, short, broad head, in which the eyes 
are placed at a distance from each other (Fig. 59). 
The wings of the first two genera are always horizontally 
“expanded; but the wings of the last genus, when at rest, 
Figure 59. are directed backward, 
touching each other. They 
have four jaws, which are 
covered with a helmet-like 
membrane, giving them an 
ugly, ferocious appearance, 
but which is really nothing 
more than the under-lip, 
with which they are ena- 
bled to seize their prey. 
The larvae, or grubs of 
the dragon-fiy, live in the water. Those of the genus Lz- 
bellula are short and thick; those of Zshna are longer; 
and those of Agrion are very slender, and the smallest of 
all. ‘Their color is generally brownish green; their head, 
thorax, and hind body distinctly separated, and the latter 
composed of ten ringlets. They swim quite well. Their 
breathing is effected by the hind extremity of the body, 
as any one may observe who will take them out of the 
water and leave them so about a quarter of an hour, and 
then put them into a flat vessel scarcely covered with 
water. : 
After spending ten or twelve months under the water, 
these larve transform themselves into the perfect-winged 
insect, and henceforth live in the air. Their metamorpho- 
sis may be almost daily observed from the month of April 
until October, but occurs principally in the months of May 
and June. But this transformation does not take place in 
the water, but out of it; and, when’ ready for their meta- 

The Agrion. 
