NORTH AMERICAN CADDIS-FLY LARVZE. 
to the point of the frons, where the two meet (figure 47) ; a black 
band encircles the hind margin of the head; the frons is marked 
with a longitudinal stripe (figure 49), and is margined in front 
with brown; the mandibles are black; otherwise the head is straw- 
yellow. 
The Thorax.—The prothorax is completely margined with 
black, except a narrow space at the base of each coxa; there is a 
dark-brown mark in the shallow transverse furrow, and an ill- 
defined brown area in front of the black caudal margin; otherwise 
the prothorax is pale yellow. The dorsal plate of the mesothorax 
is pale yellow, more or less mottled with brown, and with a border 
of dark-brown or black; in some specimens a curved black line 
crosses each caudal corner of the plate. On the metathorax the 
chitinous plates are dark-brown, more or less nearly surrounded 
by a lighter border. 
The Abdomen.—On the first segment the spacing-humps are 
well developed; a few sete arise from a small dark spot on each 
side of the cephalic margin of the dorsal hump; on the ventral 
surface there is a mound-like elevation bearing a pair of chitinous 
spots from which several sete arise ; on the ventral surface of each 
segment, three to seven, there is an oval chitinous disc, and on the 
eighth segment there is a pair of smaller discs; the gills are unusu- 
ally broad and long, from one to three or four filaments arising 
from a single stem, but the number of filaments, and even the 
number of gills, is subject to very great variation in this species; 
figure 48 diagrams the distribution of gills for an average speci- 
men. 
DEscRIPTION OF THE Case.—In length the cases of mature 
larve are from 3.5 mm. to 5 mm. They are made of irregularly- 
shaped sections of leaves, as shown in figure 50; at the caudal end 
of the case the ends of the leaves are drawn abruptly in, leaving 
a round hole considerably smaller than the diameter of the tube. 
LIMNOPHILUS COMBINATUS. 
Hasrrat.—The larve are common in the slow-moving streams 
of Michigan Hollow, McLean marshes, and other upland localities. 
Hazits.—During their early life the larve frequent the grass 
and sedges which fringe the edges of the streams. As the time for 
pupation draws near they wander from the edges where marsh 
44 
