
AQUATIC INSECTS OF FRESHWATER 

the adult, and the winged existence lasts but a few weeks; oviposition 
being conducted by the same individual for a number of days. The 
larvee of the same brood also develop unequally, some growing so 
rapidly that they de- 
vour their more tardy 
brethren. When cap- 
tured, the nymphe 
not only prey upon 
each other but upon 
any living thing kept 
with them, and the 
larvee and nvmphe are 
the most rapacious and 
destructive enemies of 
young fishes which the 
aquarlist encounters, a 
single one often de- 
stroying an entire hat- 
ching of several hun- 
dred young fishes in a 
few days. Nor are 
their attacks confined 
to young fishes, what- 
ever contains life is fair 
game to them.) | ihe 
principal families of 
the Atlantic Coast and 
Gulf States are the 
FEschinide, Libell- 
ulide, Cordullidz, 
Cordulegasteride, Ag- 
rionide, Gomphide; 
and the Calepterygide 
or Damsel-flies, Fig. 

FIG. 216, Dragon-fles, 216. The “Hammer- 
1. A&chna heros. ee 
2. Libellula pulchella. headed dragon flies 
3. Gomphus exilis. comprise the genera 
4. Argia violacea, a Damsel-fly. : 
Reduced one-fourth, Agrion, Lestes and 
Calopteryx, which frequent grassy margins of ponds, pools and swamps. 
The larger are the ““High-flying-dragon flies,” A’schna and Corduligaster, 
which frequent tall shrubbery and trees and are seldom seen over ponds 
262 
