NORTH AMERICAN CADDIS-FLY LARVE. 
RHYACHOPHILA FUSCULA. 
LarvaL Hasrrat.—The species is common throughout the 
region in all fast-running streams with stony bottoms. They are 
numerous in the permanent streams on the upland hills, but are 
far more common in the stony gorges near the lake’s level. 
LarvaL Hasitat.—Until the prepupal state is reached the 
larve build no cases, but crawl naked beneath the stones of the 
stream’s bottom. For life in this situation the flat body and wedge- 
like head of the larve are well adapted, and any form of portable 
case would be an incumbrance that would make its mode of life 
impossible. 
Foop or LArv4.—Examinations of stomachs indicate that the 
larve live on a mixed diet of animal and vegetable food, with 
animal material taken in greatest abundance. Only one stomach 
examined contained nearly pure contents of the filamentous algz, 
Cladophora. Two stomachs contained a little Cladophora mixed 
with Chironomid larve; and six stomachs contained nothing but 
Chironomid larve. In all cases where Chironomid larve were 
found they were swallowed whole, with no mastication whatever. 
PrepupaL Hasits.—In preparing to pupate the larva makes 
the first case of its life—not a portable or close-fitting case like 
those made by most Trichopterous larve, but a roomy corral-like 
inclosure of pebbles. Inside of the corral the larva spins a pu- 
parium-like sheet of silk closely about itself. Within this case 
transformation takes place. 
Preriop OF EMERGING.—Specimens were taken on the wing 
from the latter part of May until the middle,of July. It is probable, 
however, that more careful collecting will discover adults emerg- 
ing during the greater part of the summer. 
DeEscripTION oF LaArvA.—Length, 20 mm. Color in life, dark- 
green, changing to brown in alcoholic specimens. 
The Head.—The ground color is straw yellow, with dark- 
brown markings subject to slight variation, figure 184. Behind 
each eye there is an elongate subcutaneous mark of jet black; 
at the caudal margin of each side. of the head there is a jet black 
mark. On the ventral surface the head is straw yellow, except 
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