AQUATIC INSECTS IN NEW YORK STATE 321 



arranged in the form of a very irregular trapezoid [pl.26, fig.6] ; 

 all the segments of the leg with many setae [pl.26, fig.5] ; labrum 

 indistinctly five sided, with eight marginal setae, the six median 

 ones short, subeqiial in length, and equidistant from each other, 

 the lateral ones long and distant from the median ones, with 

 six discal setae, the distal pair in front of a line drawn between 

 the median pair and about as long as the median pair, the 

 median pair long and stout, the proximal pair very long and 

 slender, the distal and nie(Jian pairs in front of the distal pair 

 of sensory pits, with two lateral setae which are long and stout, 

 and with four sensory pits [pl.26, fig.3] ; the anterior tergal 

 setae of the mesothorax and metathorax divided into three 

 groups, those of the first five abdominal segments not divided 

 and their lateral extensions united with their supraspiraeular 

 setae, those of the sixth and seventh abdominal segments not 

 divided and distinctly separated from their supraspiraeular 

 setae, the posterior tergal setae of the mesothorax slightly 

 joined with the lateral groups of the anterior tergal setae, those 

 of all the other segments straight and distinct; the supraspir- 

 aeular setae not extending on to the annulet of the posterior 

 tergal setae, those of the seventh abdominal segment not con- 

 'aisting of more than three or foiur setae; the infraspiracular 

 setae of the abdominal segments of medium size, oblique, those 

 of the seventh segment not reaching cephalad as far as the spir- 

 acle; the anterior and posterior sternal setae of the thoracic 

 segments distinctly separated, their posterior sternal setae di- 

 vided longitudinally into two distinct groups; the pedal setae 

 circular in outline and separated from the sternal setae; the 

 sternal setae of the first five abdominal segments forming a 

 continuous group, those of the sixth and seventh abdominal 

 segments divided longitudinally^, those of the seventh segment 

 not consisting of more than three or four setae [pl.29, fig.4]. 



Cocoon. Brown; oval in outline; and attached along the mid- 

 dle line of the leaf of a sedge (Juncus). Length, 11mm; width, 

 6mm. 



Described from specimens loaned by the Museum of Compar- 

 ative Zoology and collected by Mr H. G. Hubbard in marshes of 

 Detroit river, Michigan, in August 1873. 



Donacia aequalis 



Larva. Mandibles bidenticulate, with one or two well marked 

 teeth within [pl.26, fig.8] ; eyes apparently wanting; each seg- 

 ment of the leg with a number of long setae [pl.26, fig.l2] ; the 

 labrum distinctly five sided, the front margin deeply emarginate 



