NORTH AMERICAN CADDIS-FLY LARV. 
two to four inches above the level of the water. The water below 
was a spring pool which never rises to the level to which the larve 
had climbed. These pupe were put in cages with no water, and 
successfully emerged about ten days later. 
Foop oF Larvai.—The larve feed on shallow raspings from 
the sticks and vegetation of the waters they inhabit. Stomachs 
examined contained a large amount of the outermost tissues of 
plants and sticks, together with about the same amount of sessile 
diatoms, and an occasional fragment of some minute crustacean, 
perhaps swallowed by accident. 
PERIOD OF EMERGENCE.—Specimens in captivity emerged dur- 
ing the latter part of June. 
DescrIPTION oF LAarvA.—Length, 25 mm.; breadth, 4mm. In 
attitude the larve maintain straight abdomens, slightly curved 
thorax, and head turned well under the first thoracic segment, 
with the mouth parts between the front legs. The coxe are carried 
with their distal ends directed toward the median line of the body, 
which brings the bases of the tibiz almost together. 
The Head.—In color the head (figure 71) is light-brown, with 
very faint speckles of a shade darker over the dorsal and caudal 
portions ; an unspotted area begins at the hind margins of the eyes 
and extends around the caudal portion of the ventral surface of 
the head. The sete on the dorsal surface are deep-black. The 
frons is without pattern, except the faintly darker muscle-attach- 
ment spots. The mouth parts are often carried almost entirely tele- 
scoped within the cavity of the head; they have the general color 
of the head, except the mandibles, which are deep-black; in form 
the mandibles are broad and scoop-like, but slightly indented on 
the anterior margin. 
The Thorax.—The prothorax has the dorsal furrow very 
feebly developed. In color the dorsal surface is pale straw-yellow 
with a few inconspicuous small specks of a slightly darker shade. 
The chitinous plate of the mesothorax is colored like the dorsal 
surface of the prothorax, its narrow caudal margin is conspicu- 
ously black, and there is a small, roughly triangular spot of black 
near each lateral margin, about midway between the front and 
hind margins. The deep-black coloring of the pleural suture is 
limited to a spot near the base of the coxa, and does not extend 
54 
