LIMNOPHILID&. 
of higher plants, which probably forces the larve to feed upon 
diatoms throughout their lives. 
Periop oF EMERGING.—The species is on the wing in greatest 
numbers about the middle or latter part of April, but late comers 
have been found in our locality until the latter part of August, 
and Vorhies, in Wisconsin, found several egg masses on October 
12th, and one egg mass as late as November 2d. Our first speci- 
mens were taken on bright days during the very first part of April, 
when snow in nearby drifts was still piled to a depth of several 
feet. At such times the adults are not uncommon. 
In leaving the cases the pupz sometimes follow the usual 
method of breaking through the end of the case. More often, 
however, they tear out a section of the side wall, leaving a long, 
jagged hole in the side of the case. 
a 
PLATYPHYLAX DESIGNATUS. 
96. Larva. Head and thorax. 99. Larva. Frons. 
97. End of pupal case. 100. Larva. Distribution of gills. 
98. Larva. Gills. ror. Case. 
DESCRIPTION OF THE LaRvA.—Length, 18 mm.; breadth, 4 
mm. In life the body is light-green in color. In form it is dis- 
tinctly curved, and apparently incapable of straightening. 
5 65 
