•684 Wisconsin Academy of Sciences, Arts and Letters. 
ones, almost anywhere along the lake shore where stones abound. 
The pupa lies with its ventral side toward the axis of the whorls 
of the case, the slit in the anterior closing membrane being so 
placed that it lies at about the level of the labrum, and across 
it from side to side. The body extends around somewhat less 
than one whorl, and at its posterior end a sieve-membrane is 
formed, leaving thus more than an entire whorl empty. This 
surplus cannot be cut off as would be done by larvae with 
straight cases. 
Habits and Occurrence.— This larvae is easily obtainable 
along the rocky shores of the lakes, where it is often in such 
shallow water that it may be taken from rocks reached from 
shore. It ranges out to a considerable depth also, specimens 
having been taken from a depth of eight or ten feet. All other 
larvae of this genus whose habitat I have been able to determine 
from the literature, live in (or near) flowing streams. Thus, 
H. sperata has been taken from “mossy rocks exposed to the 
sun, not in the stream itself, but kept constantly humid by drop¬ 
ping water,” McLachlan, (1880). H. zealandica is reported 
by Hudson (1904) from streams containing trout, and revelieri 
from shallow streams and (probably the same) from torrents. 
Our American II. arenifera is known only from a case descrip¬ 
tion from the Cumberland River, Lea (1834). I have collected 
■borealis from Lakes Mendota and Monona and Devil’s Lake. 
The images are very common in late June and early July, 
when they may be taken in large numbers from vegetation near 
the lakes. Specimens were also obtained at Trout Lake, in 
Vilas County. I was unable to observe the method of oviposi- 
tion, probably" because it takes place after nightfall. Certainly 
the females must descend beneath the water to place the eggs 
where they are found. Furthermore, I should expect the in¬ 
sect to come up quite unwetted, owing to its excessive hairiness. 
It is certain that many Trichoptera fall upon the water and rise 
:again at will. 
(PL LI I, Fig. 6. PL LVI, Figs. 12-22.) 
