294 NEW YORK STATE MUSEUM 



gg Antennae consisting of three segments 



li Abdomen cylindrical, obliquely truncate at apex, the 

 I chitinized apical projection on the dorsal aspect and 



projecting- dorsad Cioidae 



hlh Abdomen subcylindrical, not obliquely truncate at apex, 

 and the chitinized apical projection at apex and sub- 

 horizontal Lagriidae 



Family chrysoxielidae 



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 sui'face 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 



I mag OS 



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 onNymphaea advena, 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 



