NORTH AMERICAN CADDIS-FLY LARVE. 
DescrrpTioN oF Eccs.—During the latter half of June egg 
masses may be found on the under surface of floating leaves and 
sticks. The gelatinous mass is disc-shaped, measuring about 5 
mm. in diameter. Inside the gelatin the eggs are arranged in a 
spiral of about 200 eggs, figure 173. 
The egg masses occur in very great numbers, often completely 
covering the under sides of submerged leaves, or even placed one 
on top of another. 
DescrIpTION oF CasE.—In form the case is an elongate cornu- 
copia, usually measuring 1.5 cm.—2.5 cm. It is made of thread- 
like sections of the epidermis of leaves, or the fine ribs of leaves, 
wound in a spiral. The leaf sections are cut and fitted end to end 
and side to side with wonderful skill and precision. 
By the time newly-hatched larve have left the gelatinous egg 
mass, they have constructed irregular, web-like cases of transparent 
silk. To this silk case silt adheres. After two or three days from 
the time of hatching the silk case is replaced by the characteristic 
spiral case of the species. 
SETODES GRANDIS. 
Hasirat.—lIn the beds of Potamogeton americanus in Spen- 
cer Lake the species occurs in great abundance. At an earlier date 
Professor Comstock found the larve abundantly among the 
aquatic vegetation at the north end of Cayuga Lake. During 
recent years, however, it has been impossible to find a single speci- 
men in this situation. 
Hasits.—In Spencer Lake the larve feed on Potamogeton 
americanus. On this plant they, with their brilliant green color 
showing through their transparent cases, can hardly be distin- 
guished from the stipules of the leaves of their food plant, which 
they resemble exactly in size and form. 
Vorhies experienced great difficulty in distinguishing the larve 
from the spine-like leaves of Ceratophyllum, on which he found 
them common in Wisconsin. 
Before pupation one side of the cephalic end of the case is 
made fast to the host plant, leaving the case projecting in a de- 
cidedly spine-like manner. The pupa, like the larva, is brilliant 
green and shows its color distinctly through the transparent case. 
102 
