364 NEW YORK STATE MUSEUM 
white. On each side is a triangular shaped spot which marks 
the position of the future respiratory filaments of the 
pupa. The basal half of the thoracic proleg is fuscous, its 
apex paler. Extending from the base of the proleg to the first 
abdominal segment is a broad, dark line with sinous margins. 
The abdomen is fuscous, paler at the sutures and on the ventral 
surface. The underside of the last two or three segments is 
nearly white. The hooks (about 100 rows, 12 in a row) forming 
the margin of the sucker are dark brown [p1.34, fig.11-12]. In 
some specimens a fine fuscous line extends the whole length of 
the ventral surface on the median line. Just before pupation the 
developing ventral hooks of the pupa become visible. Though 
retracted in nearly all the material studied, I have found that 
the blood gills of the last abdominal segment consist of three 
unbranched lobes. 
Pupa ([pl.34, fig.10]. Rich brown in color; the two tufts of 
thoracic respiratory filaments (one tuft on each side) are each 
divided primarily near the base into four main branches, the 
two inner ones larger than the outer ones, each branch again 
dividing two or three times into twigs, so that upward of 60 
filaments may be counted. On the ventral surface close to the 
posterior margin of the last six abdominal segments are four 
larger upward curved spines; on the dorsal surface near the 
base of each abdominal segment is a close row of spines pro- 
jecting caudad, and on the dorsal and lateral surface of these 
segments, a short distance from the margin, is a row of fine 
spines projecting cephalad. The last named are not quite so 
close to the margin, nor are they nearly as large. In the figure 
the segments are contracted, and the caudad projecting spines 
appear to be attached to the posterior margin, whereas they 
belong to the middle of the dorsal surface of the following seg- 
ment. At the apex of the last segment are two stout hooks 
projecting dorsad and cephalad. The pupal cases consist of a 
dark matted mass of silk, of no definite form, secreted on the 
rock, and in which the pupae are partially imbedded. The pupal 
life lasts about eight or nine days. 
From Professor Kellogg (Leland Stanford Jr University, Cal.) 
I received specimens of larvae and pupae which agree very 
closely with those just described. These specimens (collected on 
the university campus)appear to differ only in that the labium of 
the larvae possesses but three bristles in each row on the ventral 
surface. Specimens from Professor Aldrich (Idaho) are identical 
with those from New York State. 
