322 NEW YORK STATE MUSEUM 



with eight marginal setae, the six median setae equidistant from 

 each other and subequal in size, the outer ones more distant 

 and longer, with six discal setae, the distal and median pairs 

 almost in a line and subequal in length, the prbximal pair long 

 and slender, with two lateral setae placed near to the proximal 

 margin of the labrum, and with four sensory pits [pl.26, fig.ll] ; 

 the anterior tergal setae of the mesothorax and metathorax 

 divided into three groups, those of the first seven abdominal 

 segments continuous but slightly broader at the middle of ab- 

 dominal seginents two, three and four, the posterior tergal setae 

 continuous, those of the seventh abdominal segment extending 

 as far as the spiracle; the supraspiracular setae of the first six 

 abdominal segments divided transversely, the cephalic group 

 being joined to the outer ends of the anterior tergal setae and 

 the caudal group triangular in outline and midway between the 

 anterior and posterior tergal setae; the infraspiracular setae 

 almost as broad as the segment, oblique; the anterior and pos- 

 terior siternal setae distinct, the posterior sternal setae of the 

 thorax divided longitudinally, the sternal setae of the first six 

 abdominal segments distinct and not divided longitudinally, the 

 sternal setae of the seventh abdominal segment small and di- 

 vided longitudinally into two groups, the lateral margins of the 

 sternal setae of the first two abdominal segments slightly co- 

 alesced with ithe pedal setae; the pedal setae broad and well 

 marked [pl.30, fig.l]. 



Pupa. White; the legs, wing pads, and antennae not closely 

 attached to the body; tlie second and third segments of the 

 antennae subequal; pronotum with a well marked median line- 

 like grove and a prominent tubercle on each side in front; the 

 first ventral abdominal segment as long as the next four. 

 Length, 8mm; width, 3mm. 



Cocoon. Dark brownish, oval in outline, attached to the side 

 of the roots of Sagittaria and much wider than the roots to 

 which they are attached. Length, 8mm; width, 4mm. 



Described from specimens collected on the roots of Sagit- 

 taria latifolia and Sagittaria rigida at Ithaca 

 N. Y. 



Donacia emarginata 



Larva. The mandibles with two median toeth and well marked 

 denticulations within, the surface with two or three setae [pl.26, 

 fig.l8] ; the eyes apparently wanting; the three segments of the 

 legs with numerous setae [pl.26, fig.l6] ; the labrum four sided, 

 with eight marginal setae, the six median setae adjacent, sub- 

 equal in size, and at the bottom of a slight emargination, the 



