INTRODUCTION. 
FAMILY CHARACTERS OF TRICHOPTEROUS LARV&. 
Prolegs fused in median line to form an apparent tenth segment. 
DorRSAL 
TRACHEAL BREADTH | MESONO- | METANO- | FEMUR OF 
FAMILY SURFACE 
GILLS. of UaBrum|°* LABRUM TUM TUM HIND LEG 
Filamen- | With row | Broader Chitinized | Soft Not 
CALE OLLIE tous of 20 or than long divided 
more 
heavy 
bristles 
In Normal Much Chitinized| 2 narrow | Not 
ODONTOCERID& bunches longer plates divided 
than crossing 
broad median 
line and 2 
small 
lateral 
plates 
s Absent, Normal Broader Chitinized | Soft Not 
SARICOSTOMATID | single or than long divided 
bunched 
M In Normal Broader Chitinized | Soft Not 
OLLANID# bunches than long divided 
or 
branched 
L Absent, Normal Broader Chitinized | Soft Divided or 
EPTOCERIDA single or than long apparently 
bunched so 
P Un- Normal Broader Soft or Soft Not 
HRYGANIDZ, branched, than long | with one divided 
lateral pair of 
series with minute 
black hairs plates 
L Single, Normal Broader Chitinized| With 3 Not 
TMNOPHILIDAE bunched than long pairs of divided 
or plates 
branched. 
Never with 
black hairs 
ments. This armature, except that of segment one, is subject to 
so much individual variation that it is of little systematic impor- 
tance. 
The caudal abdominal segment bears long, slender processes 
armed with long spines. These are probably used, like the long 
spines on the labrum, to keep the mesh of the pupal case free from 
entangled silt. 
Toward the end of the pupal instar it is possible to see many 
of the adult characters through the pupal skin. Thus the armature 
of the legs and the character of the genetalia can be easily com- 
pared to those of the adult. 
15 
