270 Annals Entomological Society of America  [Vol. VII, 
I believe that the thick cluster of bristles on the outer edges of 
the labrum are used in removing the microscopic plants 
from the meshes. 
7. The larva used its front legs in combination with the 
mandibles for seizing, and holding in position until fastened 
with silk, any bits which it might wish to weave into its tube 
or use as supports for the net. 
8. The position indicated in Plate XX XVII, Fig. 5 is the 
one usually assumed by the larva in spinning its net and in 
feeding. Since no pebbles or vegetable bits were placed in the 
groove, the larva spun its tube entirely of silk, and so its position 
could be clearly seen. The larva rested ventral side up with 
the hooks of the anal prolegs fastened in the roof of the tube. 
Usually only the head and thorax protruded from the entrance, 
but if the larva needed to reach out farther than the stretching 
of the abdomen would permit, the body was moved forward 
in the tube. The front legs were directed forward, and were 
used chiefly for clinging on to the net during its construction. 
The tarsal claws were passed rapidly along a thread near to the 
one which was being spun. The second and third pairs of legs 
were also used for holding on, being stretched out on either 
side and shifting only as the movements of the larva demanded 
it. 
9. Feeding Habits——The larva never was so intent upon 
finishing its net but that it stopped and picked off particles of 
food adhering to the threads, ate them and then continued its 
labors. As soon as it finished its net, and while the mesh was 
practically clean, I put insect food (Simulium larve and Hep- 
tagenia nymphs) into the groove. One specimen was used at 
a time, and the net was effective in holding back food as the 
water filtered through. The larva siezed any intruder almost 
immediately with its front legs and mandibles and pulled it 
down toward the mouth of its tube. It was not without a 
struggle that its victims were subdued, sometimes as long as 
five minutes being required. The larva seemed to swallow its 
food whole, with little chewing of it, and shoved it into its mouth 
with its front legs. Perfect or only slightly mutilated speci- 
mens of Chiromid larve and Heptagenia nymphs found in the 
cesophageal region seemed also to point to this method of 
feeding. 
