
AQUATIC INSECTS OF FRESHWATER 

and waterways. These attack all winged insects, none seem too large to 
escape their onslaughts; but their principal prey is the evening flying 
Diptera and juicy, winged insects. The “Swift-flying dragon-flies’’ com- 
prise the genera A’schnina, Gomphus, Anax, Cordulia, Tramea, Libellula, 
Celithemis and Diplax; some of them nearly as swift of wing as A‘schna 
but not capable of as lofty and long-sustained flight. Dragon-flies are 
local in their habits, rarely flying far from their accustomed haunts, except 
in occasional cases of migration. Belostoma, Notonecta, Ranatra and 
other predaceous insects prey on the younger Dragon-fly larve, and frogs 
will take the perfect insect, as will also some of the birds, notably the Fly- 
catchers. It may be noted that Dragon-flies are most inveterate enemies 
of the mosquito in all the stages of its development, attempts having been 
made to introduce them extensively to aid in exterminating this pest 
The most common species of Dragon-flies in the Eastern and Middle 
States are Gomphus exilis, Cordulegaster maculatus, Aischna heros, A. 
clepsydra, Anax junius, Tramea carolina, Libellula pulchella, Celithemis 
elisa, Diplax ribicunda, Calopteryx maculata, Lestes unguiculata, Epicordulia 
princeps and Argia violacea. Fig. 216. Agrion is not found in the 
Eastern section of the United States. 
Cappice-Fires or Capprice-Worms belong to the order of Trichop- 
tera, signifying hair-winged. They are mothlike insects usually having 
four membranous wings with numerous longitudinal veins, few cross veins 
and more or less clothed with hairs, which, at rest, are folded against 
the abdomen, the hind wings being usually the broader. They are com- 
mon near ponds, streams and lakes and frequent shady places, resting on 
leaves and twigs, rarely flying during the day. The eggs are laid in gela- 
tinous masses attached to water plants. The larve, known as Rock-worms, 
are aquatic, elongate and cylindrical in form with a tough horny head and 
thorax and a soft thin-skinned abdomen; which construct protective cases, 
open at the ends, of any available materials, leaves, twigs, sand, shells and 
small stones, all spun together by means of silk threads, to protect the 
Caddice-worm from predatory insects and other natural enemies. ‘They 
breathe by tracheal gills at the side of the abdomen, and live several 
months in the larval condition, passing the pupal stage in the cases, both 
ends of which are then sealed with a silk netting. he final metamor- 
phosis takes place above the water on plants or on the banks, the fly 
emerging from the pupa fully developed and immediately takes to flight. 
The food of the larve is principally vegetal, but one family is carnivorous 
and feeds upon small insect larve. There are more than 150 North 
American species, the more generally distributed of the Eastern and 
Middle States being PAryganea interrupta, Fig. 213, Limnephilus rhombicus, 
263 
