HABITS AND ANATOMY OF THE LARVA OF THE 
CADDIS-FLY, PLATYPHYLAX DESIGNATES, WALKER. 
C. T. VORHIES. 
The larvae of the caddis-fly, Platyphylax dcsignatus Walk., 
are found in great numbers in a certain group of cold springs' 
on the southern shore of Lake Wingra, near Madison, Wisconsin. 
There are several other large springs about the shoves of the 
same lake, but the larvae are not abundant in any of the others 
and in some are not found at all. The conditions found in the 
group inhabited by the larvae are as follows: cold water in 
abundance throughout the year at a temperature of 8° C. never 
freezing in the most severe winter weather: plenty of clean 
rather fine sand, with numerous coarser particles; many larger 
stones, under which the larvae lie hidden during the daytime; 
Water-cress, Nasturtium Officinale, in great quantities, and some 
water-milfoil, Myriophyllum, on which plants the larvae feed. 
A few larvae may be found during the day under the denser 
clusters of water-cress, where there is little light, but not much 
evidence of feeding by day may be seen. As the loose stones- 
under which the larvae are hidden are often at a distance of 
five or six feet or even more from the food plant, and as the in- 
testine is always found distended with food in these specimens, 
the conclusion is at once forced upon us that they feed almost 
entirely at night. The fact that during the day the larvae in 
dishes in the laboratory cluster in the darkest shelter obtainable 
lends support to this conclusion. When a loose stone is lifted 
under which dozens of larvae are gathered, what at first appears 
to be a mass of sand begins to heave and move and soon resolves 
itself into a number of individual larval cases, each being labori- 
