AQUATIC INSECTS IN NEW YORK STATE 295 
they can carry a supply of air with them. Many water beetles 
carry a supply of air under their elytra; others carry it on the 
ventral side of the abdomen and thorax. This supply is re- 
plenished and purified by the insect going to the surface of the 
pond from time to time. By the larvae, pupae, and adults 
of the Donaciinae, neither of the above methods is in use. In 
the following pages the method these insects pursue for 
obtaining a supply of air will be described. The account is 
based on studies made on the life history of Donacia pal- 
mata, which occurs abundantly throughout the summer at 
Ithaca. 
Specimens of Donacia palmata were found most 
plentiful on the plants of the yellow pond lilies growing in the 
lagoon extending from the south side of Fall creek just above 
where it empties into Cayuga lake. It is known as the White 
Lily pond, because it is the only place where this plant is found 
at the head of the lake. This lagoon extends off from the main 
stream in a rather sinuous course for about 200 yards. At no 
place is the water more than 3 feet deep. The bottom consists 
of soft loamy ooze about 2 feet deep. It is in this ooze that 
the underground stems of the yellow pond lily grow. In order 
to obtain the stems containing larvae, it was necessary to get 
into the water and pull them up from the bottom of the ooze. 
Along the banks of the lagoon there was a luxuriant growth 
of Sagittaria, Pontederia, Polygonum sagittatum, 
Scirpus, and Typha. It was along here that the larvae 
and pupae of Donacia aequalis and Haemonia 
nigricornis were obtained. The conditions existing are 
well shown by plate 20, where the luxuriant shore growth is 
represented in the foreground, while the water just beyond is 
almost hidden by the leaves of the yellow pond lilies floating 
on its surface. 
In the early summer, while the water is deep or the stems are 
not long enough to raise their leaves above the surface of the 
water, the eggs are laid on the underside of the leaves of the 
large yellow pond lily, Nymphaea advena. Growing in 
