HUNGERFORD: AQUATIC HEMIPTERA. PA 
and no water bugs came forth in the pool transplanted in the 
laboratory. Thus the ‘Cattail Pool” comes in the category of 
the temporary pools that provide range for a spring generation 
of bugs, but afford no permanent abiding place for this nur- 
tured population. 
A Permanent Pool. 
The writer is unable to say what has been the past history 
of Bool’s Backwater at Ithaca, New York, but from the topog- 
raphy of its location and the prevailing climate he believes 
it to be more or less permanent in its nature. 
The chief interest in this pool was the presence of the over- 
wintering fourth instar nymphs of Palmocorizxa buenoi in large 
numbers. There were some other corixids but not in confusing 
numbers, and the place was chosen to follow the development 
of the P. bwenoi in nature. 
Near the upper end of this Backwater there was a little 
shallow pool connected by a narrow neck of water to the main 
body during normal times. A constant stream of fresh water 
came into the main body near by, but made connection with 
this little pool only in times of high water. The nymphs of 
-Palmocorixa were here by hundreds. Twenty-three were 
counted as they foraged in a space two square inches in extent. 
Under the life history of Palmocorixa will be found the ad- 
vancement of the development of these bugs. 
April 19 the Arctocorixa alternata were mating while the 
P. buenoi were still in the stage in which they overwintered. 
May 9 a wind from the northwest backed the water up so 
that the little pool was broadly connected with both the Back- 
water and the Bool’s brook. Yet when it was examined the 
boatmen were seen upon their former foraging grounds though 
the shore line was several feet beyond the normal. May 11 
the water was backed to its former level again. Toward the 
last of the month the little pool was obliterated by high water 
for several hours at a time but without changing the population 
to any great extent. Polliwogs and minnows invaded the pool 
in early June, and there was some concern as to the effect the 
latter would have upon the corixid nymphs which were now 
attaining the adult state. June 8 the water was two feet higher 
than usual, and for the next week the shore line was six feet 
out from the normal. The grass along the east bank of the 
Backwater was submerged and came to be slime coated with 
