€76 Wisconsin Academy of Sciences, Arts and Letters. 
Case. —Length, 18-22 mm. Width, 4-5 mm. at anterior 
end, a little narrower posteriorly; cylindrical, beautifully con¬ 
structed of rather evenly sized sand grains, curved; open at both 
ends, hut the posterior edge usually turned in so as to narrow 
the opening. A dorsal hood at the anterior end. 
The anterior end of the pupal case is composed of larger, 
irregular stoijes, sometimes a few being added to the posterior 
end also when it is closed. It is fastened at both ends to the 
lower surface of a stone, large clusters being formed in a favor¬ 
able location. 
Habits and Occurrence .—The habits of this larva have been 
described in an earlier paper (1905). To the observations 
made at that time may he added the following. The food of 
the newly hatched larvae differs somewhat from that of the older 
ones. Immediately after building a case, they begin to feed 
and for some time their food seems to consist almost entirely of 
simple algae, diatoms, etc., which they gather from the rocks 
in the spring or stream. 
After several unsuccessful attempts, a full-grown larva was 
successfully transferred to a glass tube of the proper size, and 
by this means what took place after the closing of the pupal 
case could be observed. Indeed, the process of closing was 
watched, but nothing worthy of note was seen. The closing of 
the case was completed Mar. 11. On Mar. 12 the first abdom¬ 
inal segment of the larva w^as much constricted, and the tho¬ 
racic segments were stretched apart and immobile, evidence of 
the pupa taking shape within. The legs were thrown into posi¬ 
tions unnatural for the active larva, which if taken from the 
case at this time is of course helpless. On Mar. 15 the hairs 
of the lateral line of the pupa were just discernible through the 
larval skin, and on the morning of Mar. 16 the line showed 
plainly, very black, and the larval skin could be seen free from 
the pupa at the posterior end. At 9 a. m. strong contractions 
and crawding movements were forcing the pupa forward in the 
larval skin, causing it to split. At 12 :30 p. m. a split had ap¬ 
peared along the median line of the pro- and mesonotum, ex¬ 
tending partly across the metanotum. A distinct, very white 
line could he seen along the sides of the body beneath the old 
