666 The American Naturalist. [July, 
the laboratory, and largely excludes aquatic organisms which might 
make trouble in the cultures; while experience shows that the zoó- 
spores and oóspores of the Saprolegniacec are carried with the algz to 
a large extent. * * * The insects used may be freshly killed, and 
their chitonous covering should be broken as little as possible; but I 
have found that for winter cultures, when fresh insects are not readily 
available, an excellent substitute may be found in dead house-flies, 
collected in the fall and kept dry and exposed to the air, but protected 
from dust. Since the dry surfaces of insects are not readily wetted by 
water, it has proved useful to moisten them, whether fresh or dried, 
with aleohol, and then soak them in water for a few minutes to 
remove the alcohol. They will then, when thrown into the culture 
vessel, sink until their bodies are mostly below the surface, and so pre- 
sent a much larger area to the swimming zodspores of Saprolegniacee 
than if dry and floating largely above the surface." 
The publication of this paper will certainly stimulate the more gen- 
eral study of these interesting aquatic fungi. 
CHARLES E. BESSEY. 
