680 Wisconsin Academy of Sciences, Arts and Letters. 
the ends of the appendages with several upturned hooks. Man¬ 
dibles knifed ike, with serrate edges, longer than the labrum; 
the latter with a pair of whitish patches, each bearing five long, 
hooked hairs. Gills simple, as' in the larva, with which the 
gill formula is almost identical, Fig. 8. 
/ Z 3 4 S G 7 8 
f Case .—Length, 21-28 nun. Width, 6 mm. A nearly straight 
tube of even diameter, strongly built, composed of coarse sand 
and gravel irregularly placed; often with the peculiar seeds of^ 
Potamogeton. and occasionally a mollusc shell, used in . its con¬ 
struction. A dorsal hood at the anterior end. The posterior 
end is rounded and partly closed by a membrane, leaving only 
;a small circular or lobed aperture. A stick of greater or less 
length, usually a section of a stem of Potamogeton is fastened 
to the dorsal side of many cases, projecting beyond the posterior 
end. One of these measured had a stick 46 mm. long project¬ 
ing 35 mm. beyond the case, making a total length of 62 mm. 
for case and stick. 
The pupal case is shortened somewhat, its length being 22-24 
mm. The anterior end is closed by a sieve-membrane, while 
the posterior end is closed by a membrane with (usually) a 
single opening, showing in most instances, a tendency to a four- 
lobed shape. 
Habits and Occurrence. H-These larvae live along gravelly 
bottoms in the lakes, in a depth of from two to four feet of 
water. They seem difficult to get by the ordinary dredging with 
a net, and as long as this means alone was used only a few 
empty cases were found. But, at least in the spring, numbers 
may be found attached to submerged sticks and logs, particu¬ 
larly if these have an irregular or roughened surface. The 
<cases are nearly always attached at the anterior end as though 
