891.] Proceedings of Scientific Societies. 405 
marshy stretch necessary to a free growth of the rushes. At all of 
these ponds the first three species of Donacia were abundant, but only 
at Butler’s did we find swué#z’s. At that pond were many specimens, 
some resting on the lily pads, but the greater number on the stalks of 
the rushes. (Identified by Mr. Arthur Hollick as Juncus effusus L.) 
Mr. C. M. Weed, in the Bull. Ohio Ex. Sta., Oct., 1889, describes the 
abundance of subtilis in a similar situation near Columbus. My friend, 
Mr. E. M. Hulbert, tells me it is abundant near New Britain on sweet 
flag, and ‘‘no water-lilies within a mile, and no other species found.”’ 
In regard to ucida, palmata, and piscatrix, all three have been taken 
often on the leaves of the lilies and within the flowers, and there is a 
further confirmation of their lily-frequenting habits derived from an 
observation of the roots of that plant. In the operation of cleaning 
the ponds for winter, the icemen drag out the ranker growth of lilies 
and throw them, roots and all, on the banks. I have found in Novem- 
ber oval cases of a thin but tough material attached to these roots and 
containing Donaciæ in the imago and larval stages. These cocoons 
are waterproof, and enable the beetle to pass the winter under two or © 
three feet of water, or perhaps, when near the bank, imbedded in ice. 
The larvee of our American Donaciz have not been described, and 
though I have dried specimens I cannot venture to make a complete 
description. They appear to be whitish grubs, about half an inch in 
length, with the head darker, but not otherwise conspicuous. The body 
appears to taper slightly beyond the head. 
I have searched about the plants inhabited by swé#%s for similar 
cocoons, but hitherto unsuccessfully. Many of the stems are now 
€aten, possibly by its larva, and among the roots are empty cases, but 
these might have been washed up from the pond. 
The last species, *cdercudata, is known to us on Staten Island by a 
single specimen taken on Sagittaria. It was however, taken in numbers 
by Mr. Davis and myself in the cranberry bog at Jamesburg, N. J., 
on the same plant. Water-lilies occurred a few hundred yards away, 
and on their leaves were a few specimens of /ucida, but on the Sagit- 
taria only ¢udberculata. 
The life-history indicated by these observations is certainly a curious 
chapter in coleopterology. The parent beetles hover about the food 
plant proper for their offspring. They lay thereon their eggs, and the 
larvæ hatching, eat and grow fat until the approach of winter warns 
them to prepare the waterproof case for their coming transformation, 
within which the perfect insect develops and lies dormant until 
following summer, when. he emerges to repeat the cycle. It is, of 
