Vorhies—Studies on the Trichoptera of Wisconsin. 651 
In the rearing of imagos from larvae much must depend on 
the wisdom and care of the individual worker. What may or 
may not be done with larvae in the laboratory is to a great extent 
a matter of experience. Some forms, more particularly those 
from standing waters, may be rather easily managed in small 
aquaria, while others, as those from cold and swift-flowing 
waters, can only with the greatest difficulty be kept in the aver¬ 
age laboratory, if at all. Ordinary crystallization or bacteria 
dishes, 7 or S inches in diameter, provided with glass or screen 
covers, proved very useful, and could be stacked up,—a great 
saving of space. In these the larvae were kept carefully segre¬ 
gated, a strong lens being used for the separation of the smaller 
species. Bringing in the pupae from outside is a plan much 
more certain of results, but this can only be done in most cases 
after a careful study of the larvae, in order to be sure that not 
more than one species inhabits the same kind of case. In many 
instances, too, the pupae are much more difficult to find than the 
larvae. With species of Bhyaeophilidae and Ilydropsychidae,' 
however, one may adopt this plan very successfully, as I finally 
learned after vain attempts at rearing from larvae. The larval 
•exuvia of the species of these families is retained in the pupal 
case and may be readily compared with the larvae known to in¬ 
habit the same waters, or which are actually collected at the 
same time as the pupae, since this is usually feasible. 
As an example of what may be accomplished by the latter 
method, let me give an instance in my experience. On one of 
my trips to Devil’s Lake, made at the end of June, I was col¬ 
lecting along the stream when my attention was attracted by 
some soft tubes of sand, projecting from a patch of sandy bot¬ 
tom. On carefully extricating some of these I recognized that 
I had cases resembling those figured by Betten (1901). (They 
proved to be the cases of a new species of Phylocentropus.) As 
I had not previously had any such larvae, I made an examination 
and discovered that some cases contained larvae, and some, pupae, 
evidently nearly ready to transform. Collecting a number of 
these in a good-sized jar of water, I transported them to the lab¬ 
oratory, placed them in dishes of fresh water, and the next 
morning was rewarded by finding seven imagos,—some of them 
