AQUATIC INSECTS IN NEW YORK STATE 431 
fingerlike lobes, each with a marginal fringe composed of a 
single row of stout setae; and lying between these is a third, 
cylindric, nearly black in color, provided apically with three 
pairs of long black setae, and a short, pale yellow terminal joint 
[fig.7]. The middle lobe does not extend quite so far caudad as 
do the lateral lobes, differing in this respect from the described 
(European) species. It is a little more than twice as long as 
wide. Of the four small respiratory gills figured by Meinert in 
De eucephale Myggelarver nothing is to be seen in the specimen 
from which the drawing was made, though they are present 
in specimens discovered later. Caudad of the spiracles and 
lying on the dorsal surface is a triangular chitinized plate, 
the rounded vertex pointing cephalad, the basal angles each 
provided with a single short seta [fig.7p]. On the ventral sur- 
face, at the base of each of the long lateral lobes, is a short, 
semicircular lobe with a marginal row of short, black spines 
{fig.5a]. On each side of the middle line and caudad of the small 
lobes is a black ridge or keel with two black setae, the longer 
one projecting caudad, the shorter one projecting laterad; and 
extending transversely between the bases of these setae is a mat- 
ted fringe of fine, pale yellow caudad projecting hairs. 
Pupa. The pupa [fig. 4] is pale fuscous. The single observed 
Specimen assumed a nearly circular position, its caudal end 
nearly touching its head, and remaining motionless on the side 
of the glass above the water film. Normally a Dixa pupa rests 
on its side, and according to Meinert it may thrive either in or 
out of water. The length of pupal life is about three days. No 
setae were observed on any portion of its body. The breathing 
trumpets are short, with widely flaring conical mouths. There 
are eight abdominal segments besides the anal one. The anal 
segment has two long, pointed lobes with very finely serrate 
margin and a few short, terminal hairs. 
The larva on which this description is based, was found in 
Ithaca N. Y. in a slow flowing stream Ap. 11, 1902; it pupated 
Ap. 18, and emerged three days later. A number of specimens 
were found in October. 
KEY TO SPECIES OF DIXA 
In order to facilitate identification, the following key is 
offered, which must however be used with caution, as it is in part 
compiled from descriptions. 
1 Species having both the proboscis and the scutellum yellow.......... (2) 
Having either proboscis or scutellum DlACK.... 6. cece ee ee ee ee ee ee ees (4) 
