260 Annals Entomological Society of America  [Vol. VII, 
toward the hinder part of the net. It does crawl around, 
however, feeding over the whole surface of the net. It does 
not use its front legs to assist it in getting its food which is 
entirely of microscopic plants. All observations must be 
carried on in swift water, for the net collapses into a brown 
slimy mass when the pressure of the current is removed. The 
separate threads of the net are only clearly seen with the highest 
power of the microscope when it is seen that the units of the 
mesh are rectangular in shape, one dimension being about 
eight times the other. The double nature of the silken threads 
is not recognizable, as is that of the Hydropsyche’s, when ex- 
amined with a microscope. 
At times grains of sand and small pebbles are found on and 
about the large nets. I believe this to be a preparation for 
pupation, as the pupal cases are constructed of these. 
FAMILY POLYCENTROPID2. 
The nets of five genera in this family have been observed 
and described. 
Neureclipsts. 
In the year 1900 Wesenberg-Lund first noticed the plancton- 
catching-nets of Neureclipsis bimaculata in Western Jutland. 
Later he also found them at three different places in Zealand. 
They were not described, however, until 1907 when E. Petersen 
wrote an account of them. His observations were extended 
by Wesenberg-Lund (1911). The nets of this larva are trumpet- 
shaped, from 69 to 90 mm. long; the expanded mouth is 25 to 35 
mm. broad, and the hinder end about 10 mm. In some cases 
the hinder end of the tube is attached to some object, in other 
cases it floats freely. The nets show a regular variation in 
color due to the plancton caught in their meshes; in the spring 
they are brown or grayish from diatoms, in the summer bluish- 
green from the Cyanophycee. The net is kept distended by the 
force of the current and collapses into an unrecognizable mass 
when taken from the water. The plancton-organisms Bos- 
mina, Daphnia and the remains of Cyanophycez become caught 
in its walls as the water filters through and serve as food for 
the larva which is generally at the hinder end of the net. Many 
thousands of these nets span the stream in Hennebach so that 
a greater part of the water filters through them. 
