PLECOPTERA NYMPHS OF NORTH AMERICA § 13 
od of transporting nymphs is to wrap them in a clean piece of wet 
cheese cloth. This keeps the specimens moist and well supplied 
with air. Wrapped up in this manner, specimens of Perla and 
Acroneuria, which are extremely sensi- 
tive to suffocation, have been kept alive 
for a week or more. Nymphs packed in 
sphagnum may likewise be kept alive 
over a considerable period of time. In 
the laboratory where the nymphs are to 
be kept under observation for some 
time, they should be placed either in an 
aerated container or else in a pan which 
contains barely enough water to cover 
the specimens. In such pans the nymphs 
may often be seen to move their bodies 
up and down in a rhythmic manner, ap- 
parently for the purpose of better aera- 
tion. 
Rearing. In rearing nymphs, it is de- 
sirable to keep them under conditions 
closely resembling or paralleling their 
natural habitat. Where a small cold 
spring brook is conveniently located, 
and insured against disturbance from 
man and animals, the nymphs can be 
kept satisfactorily. The most satisfac- 
tory breeding cage is one made of wire 
sereen (text figure 4). These screens can 
be made in various sizes, are easily transported, and are very 
adaptable for varying conditions. For rearing the larger species, 
14 or 16 mesh screen is entirely satisfactory, but for the smaller 
species of Nemoura, Leuctra, Capnia, ete., screen with a finer mesh 
is necessary. After the nymphs have been put into the cages, 
they are placed in the water, leaving the upper half of the cage 
exposed to the air so as to allow for emergence of the adults. 
Food must be supplied to the nymphs. For the herbivores, such 
as the Pteronarcidae, Peltoperlidae, Nemouridae, and Capnudae, 
decaying leaves, algae, and detritus may be used, and for nymphs 
of the Perlidae, living insects, such as Mayflies and Chironomids, 
should be added. Inasmuch as the nymphal stage extends over a 
long period of time, it is desirable to choose the maturer nymphs 
for rearing. By observing the conditions of the wing pads, one 
tre Ee ol 
soorlrrare 
Mes tH fe ik Fe 
tt ed 
san is ' "y i 
ity cA SRN 
i" ie: 
Be is 
B| ‘& Ht 
a 
By 
fi ay 
Ha HF 
Fig. 4. Wire screen cage used 
in rearing stonefly nymphs. 
