NORTH AMERICAN CADDIS-FLY LARVE. 
MYSTACIDES SEPULCHRALIS. 
Hasirat.—The larve are common insects in Beebe Lake, 
Dwyer’s Pond, and in many of the slow, deep pools of Cascadilla 
and Fall Creeks. 
Hasits.—The species lives among the accumulation of sticks 
and rubbish on the pool’s bottom. 
The prepupal state has its beginning from the middle of May 
till the first part of June. At this time the cases are attached to 
the exposed surfaces of submerged sticks. 4 
Foop.—Stomachs of preserved specimens contained a thor- 
oughly masticated pulp, apparently of vegetable origin. 
Prriop oF EMERGING.—Specimens in captivity emerged from 
the middle of June until the first part of July. Probably under 
natural conditions their period of emerging is of considerably 
longer duration. 
DistincTivE CHARACTERS oF LArvA.—Length, 9 mm. With- 
out swimming hairs on second and third pairs of legs. 
Head.—The extent of the dark coloring varies greatly in 
different individuals. In dark specimens, figure 168, the cephalic 
part of the frons is smoky-brown; behind the brown area the 
head is pale yellow, except for several sharply-defined spots behind 
the frons; a dark mark begins behind each antenna and extends 
back to the hind margin of the head; the sides of the head are 
pale yellow with numerous dark-brown spots ; on the under surface 
the head is dark-brown without markings. 
Pale specimens have a ground color of light straw yellow, 
marked by numerous brown spots. No other markings are present. 
The Thorax.—The prothorax, like the head, is subject to great 
variation in coloration. Dark specimens, figure 168, have the 
ground color of the prothorax almost entirely dark-brown, almost 
obliterating the mottling ; in such specimens a narrow, light-colored 
line encircles each “shoulder.” In light-colored specimens the 
ground color is pale, thickly mottled with dark-brown spots. All 
intermediate gradations of coloration occur. 
The mesothorax of dark specimens is smoky, mottled with 
dark-brown, figure 168. In light specimens the smoky ground 
color is lacking. 
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