\ 
NORTH AMERICAN CADDIS-FLY LARVZ. 
all armed with powerful curved claws; the form and distribution 
of sete is shown in the accompanying figures; the apical mem- 
branous part of the front femur adjoining the tibia is somewhat 
soft and is overspread with minute conic teeth; the inner edge of 
the trochanter and femur of the front leg is armed with a single 
row of long straw-colored hairs, and the femur is armed also with 
a row of short spines on its inner edge; the second and third pairs 
of legs are much alike; the inner edge of the femur is armed with 
a line of sharply-pointed spines of two kinds—one kind, apparently 
very rigid, is dark in color and arises from well-defined sockets ; 
these spines are separated by one, two, or three spines of lighter 
color and apparently less rigidity, which do not arise from sockets ; 
the spines in detail are shown in figure 140. 
Figure 136 illustrates diagrammatically the arrangement of 
gills on the left side of the abdomen. 
DescRIPTION OF THE Pupa—Length, 1o—13 mm.; breadth, 
3—3.5 mm. 
The mandibles are strongly chitinized. The antenne reach to 
the tip of the abdomen. The dorsal plates of the abdomen and 
armature of the dorsal surface of the first segment are shown in 
figure 135; the hooks of the second series on the fifth segment are 
not borne on a single plate, but occur as independent chitinous 
pieces, forming a line across the dorsum of the segment. Figure 
137 shows the hooks in detail. A few minute sete occur on each 
segment—these are slightly longer and more numerous on the last 
segment ; the lower sides of segments I to 7 bear narrow obliquely 
downward-pointing lines of dark color; the last segment is shaped 
like an obtuse arrowhead. When viewed from above its two curved 
processes are equal to a little more than half its length. The 
lateral fringe is better developed than that of the larva; it begins 
behind the middle of the fifth segment and ends on the ventral 
side of segment eight. 
THE CasE, figure 144, is 15—18 mm. wide at its anterior end 
and about 1.5 mm. wide at its posterior end; it is constructed of 
minute twigs, root fibers, and fragments of wood cut to the proper 
length to give even and straight edges, gradually diverging toward 
the anterior end. In cross-section the outer surface of the case 
is square ; the interior is lined with a cylindrical tube of tough silk, 
which is equal in diameter to the inside diameter of the square 
86 
