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 dorsad Oi o 1 d a e- 



Mi Abdomen subcylindrical, not obliquely truncate at apex,- 

 and the chitinized apical projection at apex and sub- 

 horizontal Lagrildae- 



Family CHRYSOMELIDAEi 



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 pro legs wanting Donacilnae- 



Dorsal surface of the eighth abdominal 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 Donaciinae- 



Pupae naked, attached to the leaf surface by the apex of 



the abdomen, and blackish in color Galerucinae 



Imagos 



Prothorax not with a thin lateral margin , 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 onNymphaeaadvena, Sparganium andro- 

 cladium, Sagittaria latifolia, Sagittaria 

 r i g i d a , 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- 

 for 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 



