NORTH AMERICAN CADDIS-FLY LARVE. 
of setae on the dorsum are shown in figure 79; the underside of 
the head lacks markings except an area of small, somewhat oval, 
well-defined spots, which project forward from its caudal margin 
on each side of the median line. 
ASTENOPHYLAX ARGUS. 
79. Larva. Head and thorax. 84. Larva. Labrum. 
80. Larva. Frons. 85. Pupa. Mandible, outer edge. 
81. Pupa. Mandible, lateral view. 86. Larva. Lower mouthparts. 
82. Larva. Distribution of gills. 87. Case. 
83. Pupa. Chitinous plates of left 
side of abdomen. 
Thorax.—The color-pattern of the dorsum of the first and 
second segments is shown in figure 79; the under side is weakly 
chitinized, except for the horn on the first segment; the third seg- 
ment above is weakly chitinized, except for a median glabrous 
spot near the cephalic margin, on each side of which there is a 
dark-brown mark, bearing five or six sete; farther back and 
slightly more remote from the median line there is a triangular 
spot bearing about ten sete; on each side of the segment there is 
an elongate glabrous area marked with several brown spots, the 
cephalic of which bears about a dozen sete; the second and third 
thoracic segments bear numerous minute spines which, for the 
most part, point forward. 
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