PHRYGANEID&. 
or chunk of wood. Here they turn at right angles to the surface 
and slowly burrow into the wood until the last bit of the case is 
concealed. The operation sometimes requires several days of 
labor. When sufficient depth is reached the larva spins a silken 
mesh across each end of the case. 
Sometimes, when the bark of the log is loose, the larve take 
advantage of the natural condition and pupate between the bark 
and the wood, or they may wedge themselves into some natural 
crevice. Boring into the wood, however, seems the most common 
method of concealment. 
Foop oF THE Larva:.—Stomachs of larve taken under natural 
conditions contained green plant tissue of various species. Ap- 
parently the larve feed upon green tissue because of their habit 
of living among living plants, where the accumulation of dead ma- 
terial does not occur, rather than through any choice of appetite. 
In aquaria, among a mixture of living and dead plants, they dis- 
played no preference for either sort. Each was eaten with equal 
greed. 
DESCRIPTION OF THE LArva.—The larve of the known species 
of North American Phryganea can most easily be distinguished 
from the larve of Neuronia by the color patterns of the frons. 
In Phryganea the color is confined to a medium stripe, except in 
P. vestita, in which a pattern is entirely absent. 
The larve are slightly more slender than those of Neuronia. 
The spacing-humps are not quite so strongly developed, and the 
abdominal segments are more rounded, giving them a more pro- 
nounced scalloped appearance. 
DESCRIPTION OF THE Pupa:—The pupe of Phryganea differ 
from those of Neuronia in having long, slender, lance-like mandi- 
bles—many times as long as broad. 
DESCRIPTION OF THE CasE.—The cases of Phryganea have the 
form of straight tubes (figure 41) composed of narrow strips of 
leaf arranged in spiral form around the circumference of the case. 
The spiral of the same species is sometimes wound from right to 
left, sometimes from left to right. The cases of mature larve are 
tapered very slightly, if at all, but those of immature larve taper 
much more than do those of immature Neuronia larve. The 
young of both genera often fail to cut the leaf fragments used in 
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