INTRODUCTION. 
venient working distance, it would be hard to find a spot more 
favorably situated for work on different types of fresh-water life. 
Meruops oF CoLLECTING AND REARING.—The methods em- 
ployed in collecting and rearing the larve were quite simple. After 
the specimens were found, some were put at once into alcohol for 
future study, and some into formaldehyde for future examination 
of the stomach contents. Others were caged until the time they 
emerged, when the species could be determined. 
The cages employed were simple cylinders of galvanized 
screening, over the bottom and top of which a cloth was tied. 
These cages were placed in natural water as nearly like the situ- 
ations from which the larve were taken as was possible to find 
convenient to Ithaca. The cages were provided with food material 
and were partly submerged, care being taken to leave enough space 
protruding to give the emerged adults ample room above the water. 
In carrying living larve from place to place it was found that 
they quickly died if taken from well aerated water and placed in 
collecting jars. This difficulty was overcome by wrapping them 
in wet cloths. Experience has shown that aquatic insects will live 
for long periods of time in cloths that are kept moist, but they 
must not be left submerged. 
In studying the material in the laboratory, balsam mounts 
were made of the frons, legs, and mouth parts. When possible, 
the frons and mouth parts were reclaimed from the larval exuvia. 
This practice eliminates difficult dissections and gives beautiful 
mounts that are much cleaner than can possibly be obtained by dis- 
section. 
For examining the entire larve a binocular microscope with 
various combinations of oculars and objectives was employed. 
Many thanks are due to Professor J. G. Needham, Professor 
O. A. Johannsen, and other members of the staff of the Depart- 
ment of Entomology, Cornell University, for help and encourage- 
ment during the preparation of this work. 
DisTINCTIVE CHARACTERS OF TRICHOPTEROUS LARVA. — 
Aquatic larvee? having three pairs of jointed thoracic legs and a 
single pair of abdominal prolegs situated on the last abdominal 
segment, and terminating in a chitinous hook. All of the abdomi- 
nal segments are soft, except that some members of the family 
‘Enoicyla, of the European fauna, is terrestrial. 
8 
