NORTH AMERICAN CADDIS-FLY LARVZ. 
and never possesses a row of twenty or more heavy bristles. The 
gula is subquadrate, widely separating the epicrania. 
The Thorax.—The pronotum is chitinous. On each side of 
the prothorax a chitinous plate, differing somewhat in form in 
different species, extends forward above the base of each coxa. 
The mesonotum is chitinized. 
The metanotum lacks chitinous plates. 
The legs will offer unusual taxonomic opportunities when they 
are more thoroughly studied and the homology of the segments 
is better known. 
The forelegs are short, broad, and flat, with varying armature 
in different species. 
The middle and hind legs are slender and show great difference 
in armature, and in the relative length of the segments. In the 
hind legs of all known species, and in the middle legs of all except 
Setodes, there is a short segment at the base of the femur, which 
has led Ulmer to state that the femur is divided. It is not clear, 
however, that this segment does not belong to the trochanter in- 
stead of to the femur. Besides this suture, cutting off a sclerite 
of doubtful homology, there is, as is usual in Trichopterous larve, 
a suture near the base of the trochanter. In the Leptoceride this 
suture separates a short basal piece from a much longer distal 
piece. 
The Abdomen.—On the first segment all three spacing-humps 
are well developed. The lateral fringe is short and fine and ex- 
tends from the third to the seventh segment. The basal segments 
of the prolegs are fused to form an apparent tenth segment. The 
claws are small. 
In this family it is impossible to identify the species by frag- 
ments of the cast larval skin retained in the case after pupation. 
The exuvia is eliminated through the caudal opening of the pupal 
case as soon as transformation from the larva takes place. 
LEPTOCERUS ANCYLUS. 
The larvee are common in all streams of the region, except 
those of the highest altitudes; and they also occur on stones of 
the wave-beaten shores of Cayuga Lake. 
Vorhies, who first described the larve and adults, determined 
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