334 NEW YORK STATE MUSEUM 
quently in the little stream flowing through Coy glen, in Six 
Mile creek, and in Cascadilla creek; and have also been col- 
lected by Mr A. D. MacGillivray in a brook near Axton N. Y. 
During the early part of May the larvae are still quite small, 
the smallest found measured 2.5mm in length, and were scat- 
tered over the smooth rock bed of the stream where the water 
is swift, but only about 1 inch in depth. If removed from the 
brook and placed in vials or still water, they soon die, usually 
within a few hours. 
The larva is a curious black creature, flattened, its length 
being about two and one half times its breadth at widest part, 
each of the four intermediate segments separated from eachother 
and from the cephalic and anal portion by deep constrictions, 
thus dividing it into six distinct parts. Kellogg says (in the 
paper just quoted) that the anterior, apparently single segment is 
composed of the fused head and three thoracic segments, while 
the most posterior part is composed of the last two abdominal 
segments, the intervening parts representing each a single 
abdominal segment. The larva is footless, but each body part 
bears a pair of small unsegmented, pointed projections, situated 
on the ventral aspect of the lateral margins. The organs of 
locomotion consist of six suckers, one of which lies on the 
median ventral aspect of each body part; thus there is but one 
sucker for the combined head and thorax, and but one for the 
last two abdominal segments. By means of these suckers, the 
larva clings to the rock bed of the stream. The larva occasion- 
ally moves about on the smooth surface of the rock, from the 
necessity of getting farther into the stream as the water les- 
Sens in quantity, and perhaps also, for seeking its food—the 
diatoms on the surface of the rock. The structure of the sucker 
is well described by Kellogg (loc. cit.). The larvae breathe by 
means of small tufts of short thick tracheal gills, of which 
there is a pair on the ventral surface of each of the first to 
the fifth abdominal segments. On the last segment there are 
two pairs of much larger, thicker, fingerlike processes, perhaps 
also tracheal gills. The writer collected during May many liv- 
