NORTH AMERICAN CADDIS-FLY LARVZ. 
split-like respiratory opening on the side toward the axis of the 
whorl. Behind the caudal end of the pupa a flat sheet of silk with 
several respiratory openings crosses the interior of the case. 
GOERA CALCARATA. 
Hapirat.—The larve are found in riffles of the large streams 
of the region, both in the uplands and near the lake’s level. They 
also occur on stones in wave-beaten areas on Cayuga Lake’s shore. 
Hasits.—Little has been learned of the habits of the larve, 
beyond the fact that they are found crawling over the surfaces of 
bare, current-swept rocks from late summer until the end of 
March, when they attach their cases firmly on the exposed edges 
of stones, together with Psilotreta and a few other species of the 
rapid waters. 
Preriop oF Emercinc.—Adults emerge during the last week 
of April and the first week of May. 
Description oF Larva.—Length, 1o—12 mm. There is a 
heavy chitinous spur above each mesothoracic leg, grooved on its 
cephalic margin to fit a groove on the lateral margin of the prono- 
tum. 
Head.—The back part of the head, figure 129, on the dorsal 
surface, is flattened and slopes toward the caudal margin; in front 
of this flattened area, whose boundary passes in front of the eyes, 
the head is cone-shaped, sloping toward the mouth-parts. In color 
the entire head is uniform black-brown, except a slightly lighter 
circular patch surrounding each eye. 
The Thorax.—The pronotum, figure 129, is very heavily chit- 
inized. The cephalic margin is inset so that the lateral margins 
extend forward in sharp points. The lateral edges are thick and 
deeply grooved, apparently to fit the grooves of the heavy chitinous 
spurs of the mesothorax. 
On the mesonotum there are two pairs of large chitinous plates, 
figure 129, Above each mesothoracic leg there is a very heavy 
chitinous spur, grooved on its cephalic margin, which projects 
well beyond the cephalic margin of the segment. 
The metathorax bears four pairs of chitinous plates, figure 129. 
It is to be observed that in the European fauna the genus 
Geera has two pairs of plates on the mesonotum and only three 
pairs on the metanotum, while the genus Silo has four pairs of 
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