294 NEW YORK STATE MUSEUM 
gg Antennae consisting of three segments 
h Abdomen cylindrical, obliquely truncate at apex, the 
chitinized apical projection on the dorsal aspect and 
projecting  dorSade.. 5 0.5. oi ohiaceieneene Cioidae _. 
hh Abdomen subcylindrical, not obliquely truncate at apex, 
and the chitinized apical projection at apex and sub- 
orizontal. nisi ooo. « xjele © sine ola eee Lagriradave 
Family cHRYSOMELIDAE 
This family includes about 600 species divided into 11 sub- 
families. The larvae feed on the leaves of various plants. Two 
of the subfamilies contain species that feed on aquatic plants. 
These can be separated as follows: 
Larvae 
Dorsal surface of the eighth abdominal segment with a 
pair of pointed spines; abdominal prolegs wanting..... Donaciinae 
Dorsal surface of the eighth abdeminal segment not with 
a pair of long spines; abdominal prolegs present...... Galerucinae 
Pupae 
Pupae inclosed in a tough brownish silken cocoon, not 
Attached, and whitish in color .ci.ic. ..i63 ceeena © aeeeeeee Donaciinae 
Pupae naked, attached to the leaf surface by the apex of 
the abdomen, and blackish in color...........0.ee0e08. Galerucinae 
Imagos 
Prothorax not with a thin lateral, margin. 2... .. 5... 506 Donaciinae 
Prothorax with a distinct thin lateral margin.......... Galerucinae 
Subfamily DONACIINAE 
In our fauna this subfamily includes two genera, Donacia 
with 20 species and Haemonia with a single species. All the 
species are similar in habit, the larvae feeding on the submerged 
underground stems of aquatic plants. They have been col- 
lected on Nymphaea advena, Sparganium andro- 
cladium, Sagittaria latifolia, Sae@wgeamee 
rigida, and Potamogeton. 
It is a well known fact that in all insects that live submerged 
in water there are special modifications in structure to fit them 
tor such a mode of life. They are either provided with special 
organs for taking their supply of oxygen from the air mixed 
with the water, as tracheal gills, or they are so modified that 
