NORTH AMERICAN CADDIS-FLY LARVE. 
fragments, lined with silk. In length the tube is about 12 mm., 
and in breadth about 1.5 mm. On opposite sides are fastened 
pine needles, or grass stems, or slender sticks, paralleling the tube 
and extending well beyond its caudal and cephalic ends. 
Before pupation a sheet of silk with a slender, minute, round 
perforation in the center is spun across each end. 
TRLENODES SP. 
Hasirat.—The larve are common in the Cove, Michigan 
Pond, and many ponds and dilatations of creeks that contain 
Potamogetons and other aquatic plants. 
Hasits.—The larve dwell ameng the branches of submerged 
plants, seldom descending to the pond’s bottom. Unlike other 
species that dwell in similar places, but must crawl from plant to 
plant, the larve of Triznodes swim rapidly from place to place 
through the open water. 
Before pupation the cases are attached to the stems of plants 
or rolled in submerged leaves. 
Periop oF EmERGING.—Adults emerge about the middle of 
June. 
DisTincTIVE CHARACTERS OF Larva.—Length, Io mm. Long 
swimming hairs on third pair of legs. 
Head.—The ground color is straw yellow, figure 171; a dark 
mark on each side of the frons begins at the outer corner of the 
labrum and extends back to the hind margin of the head, with a 
narrow break behind the antenna; on the ventral surface a smoky 
area begins at the base of each mandible and extends back to the 
hind margin of the head. The gula is pale. The frons, figure 
172, is without pattern. The mandibles are brown. 
Thorax.—The prothorax is smoky on the dorsal surface, shad- 
ing to straw yellow on the sides. The chitinous supports at the 
base of the legs are dark-brown and black. A thorn-like process 
projects forward above the base of each coxa. 
On the mesothorax the scutellum is of a pale, smoky color, 
with indistinct dark spots. The pleural suture is long and narrow, 
and deep black in color. 
The metathorax bears no dorsal chitinous plates. The pleural 
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