16 NOTES ON 
venient reservoir, or they may be separated 
from aquatic plants without an additional ves- 
sel, by spreading the plants on a white cloth, 
placed in the sun. In a few seconds they will 
creep out, and may be taken up on the point of 
a feather. Of these two methods the first is 
the best; for, unless great care be taken in re- 
moving them with the feather in the latter 
method, their delicate bodies will be injured. 
When it is desirable to preserve them alive for 
some time, a portion of the plant must be kept 
along with them: this will furnish them with 
food, as there is generally an abundance of 
animalcules about their roots. 
They may be caught at most seasons of the 
year, but in severe cold weather, they descend 
to the bottom of the water, and remain in- 
active. 
Plate 2 exhibits a magnified view of one of 
these larva in a position that it frequently as- 
sumes, and also one of its natural size. When 
recently taken, in a healthy state, it exhibits the 
colours shewn in the drawing, which, however, 
it gradually loses, if kept in a small vessel. It 
is composed of twelve segments; the first is 
connected to the head, by a ring or neck, 
shorter than the annuli. When the larva turns 
