NORTH AMERICAN CADDIS-FLY LARVE. 
CHILOSTIGMA DIFFICILIS. 
Hasitat.—The larve of the species have been found in a 
very limited area of Argus Stream, in the McLean swamp. The 
stream is a small one, hardly more than a foot in width and three 
or four inches in depth. It rises in a sphagnum bog and penetrates 
a dense thicket of alder for about a half mile, when it enters a 
larger stream. Through the alder thicket the waters are in deep 
shade, and leaves and sticks litter the bottom. In this portion of 
the stream, so far as we can see, there are no differences of condi- 
tions within its waters. Yet this species, for the three years we 
have known it, has inhabited an area of the stream not more than 
a hundred yards in length. In this limited area it occurs in great 
numbers. 
Hasirs.—Until the middle of summer is past these larve rest 
or crawl slowly about over the bottom of the stream. As the 
period for pupation approaches they congregate in great numbers 
on submerged sticks or roots. Often they occupy every available 
lodging space on a certain stick, while other similar sticks of the 
neighborhood are left entirely free from their presence. Only 
the front ends of the cases are attached to the support, from which 
they project at all angles. 
Foop or THE Larvai.—Stomachs examined contained quanti- 
ties of fragments of wood and leaves, nothing else. 
PERIop OF EMERGING.—Specimens in captivity emerged dur- 
ing the first half of October, but it is probable that under natural 
conditions they emerge throughout a longer period. 
DESCRIPTION OF THE Larva.—Length, 16 mm.; breadth, 
2.5—3 mm. , 
Head.—The color is light-brown, figure 106, almost uniform, 
except the dark muscle-attachment circles and a thick stippling of 
microscopic spots; the dorsal surface, especially the frons, figure 
111, bears numerous pointed, spear-like processes, which are 
plainly evident in balsam mounts. The labrum, figure 110, is 
brown, with a darker mark behind the middle of its front margin; 
the innermost sete on its front margin are short and blade-like ; 
the outer sete of the front margin are longer, but blade-like; other 
sete of the labrum are indicated by circles in the accompanying 
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