PLECOPTERA NYMPHS OF NORTH AMERICA 11 
able to employ a few collecting implements. In the larger swift- 
water streams, a piece of wire screen may be placed in the water 
in such a way that the current sweeps the specimens against the 
sereen as they are dislodged from their hiding places under the 
stones, when the stones are stirred up by means of a stick, hoe, 
or rake. By nailing a piece of wire sereen on two short handles, 
the net can more readily be held in place in the stream (text fig- 
ure 2). 
1 
Ks 
acetate: 
=a 2° 2S Se oe 
an 85 Be 
Fic. 2. Wire screen used for collecting stonefly 
nymphs in rapid streams. 
For all-round collecting of stonefly nymphs, the sieve net is 
most desirable (text figure 3). This net may be placed in the 
stream and used as a sereen for collecting the nymphs as they 
are carried down by the current, while the collector holds the sieve 
net by the handle, and, by means of a stick, or with his feet, dis- 
lodges the specimens from underneath the stones above stream. 
The net is also very useful for dragging material out of the stream 
as one stands on the bank, and after specimens have been collected, 
it serves, likewise, as a washing sieve, and much of the detritus 
