AQUATIC INSECTS IN NEW YORK STATE 439 



the posterior margin of the second abdominal segment. Eight 

 segments are present besides the short anal segment. On the 

 dorsum of each segment, toward the caudal margin, is a trans- 

 verse band of stout, black bristles. Each band is composed of 

 five or six rows. The arrangement of these bristles (the longest 

 of which are about one third as long as an abdominal segment) 

 is shown in figure 11. The anal segment is composed of two 

 lobes with a single apical bristle. After two to four days of 

 pupal life, it transforms into the adult. 



Genus dia]\<iesa Meigen 



This genus has long been known to occur in Greenland, but 

 has not, till now, been recorded from the United States. In 

 1898, Lundbeck described three new species from Greenland, 

 one of which, D. a b e r r a t a , he considers the species which 

 Staeger erroneously (?) identified as D. w a 1 1 1 i i . 



Antennae of the female eight jointed, the basal disklike, the 

 intermediate ones rounded, the last cylindrical. Antennae of 

 the males usually plumose and 14 jointed. Eyes oval; the front 

 wide and flat. The eyes and the wings resemble Tanypus. The 

 cell M is separated from the cell M ,^2+3 by a cross vein, as in 

 Tanypus. The fourth tarsal joint is shorter than the fifth. 



Diamesa Waltlii Meigen 



1838 D. waltlii Meigen, Syst. Beschr. 7:13, 1 



1846 nivoriundus Fitch (Chironomiis), Winter Insects of Eastern 



New York nee O r t h o c 1 a d i u s nivoriundus Johnson, (?) 



Cat. of New Jersey Diptera 



This fly occurs, sometimes abundantly, in this State from Jan- 

 uary to April. Fitch's description is rather indeterminate, but 

 I believe it to belong to the species which is described below. 

 I have compared it with specimens from Europe, with which it 

 agrees in all particulars. According to Lundbeck [Diptera 

 Groelandica, 1898], D. Waltlii does not possess cilia on the 

 posterior margin of the wing, he quoting Meigen as authority; 

 the European specimens which I have do have these cilia, as 

 do also the American specimens; and I therefore believe that 

 a b e r r a t a Lundbeck is also a synonym. 



Male. Black. Head black, including eyes, mouth parts and 

 antennae, the latter densely covered with long, dark brown hair. 

 Its first joint enlarged, disklike, the second twice as long as 

 broad, the following 11 a little shorter than bjoad, the 14th 



