
AQUATIC INSECTS OF FRESHWATER 

prominent eyes, filiform antenne, long and full thorax and segmental 
abdomen. ‘This order is now restricted to a few families in the United 
States, including the Dobsons or Sialide, the May- or Shad-flies or 
Ephemeride; the Stone-flies or Plecoptera; the Dragon-flies or Odonata; 
and the Caddice-flies or Trichoptera. 
Dossons belong to the family of Sialiade, and include the Fish-flies, 
Hellgramites, Alder-flies and others of diverse popular names. They have 
four thin, broad, net-veined wings which are folded when at rest. All 
are weak flyers with legs scarcely able to support the body. The mouth 
parts are developed for biting, the abdomen long and slender, the antenne 
long, the head broad with protruding eyes, and the mandables well developed. 
Of the Fish-flies or Sialis there are but two species, S. imfumata and S. 
americana, both small insects which frequent vegetation on the banks of 
streams. The eggs are laid in white cottony masses on plants overhang- 
ing the water, on bridges, piers, etc., into which the larvee drop when hatched. 
The largest species of Dobson is the Horned Corydalis, C. corinita, which 
has a spread of wings of over five inches and is quite generally distributed. 

FIG. 211. Hellgramite, larva 
of the Dobson. FIG. 212. Horned Dobson, Corydalis corinita. 
The larve are known as Dobsons, Hellgramites, Bugies, etc., and are exten- 
sively used as bait for game fishes. They live under rocks and 
258 
