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 DIAMESA 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. aberrata, he considers the species which 
Staeger erroneously (?) identified as D. waltlii. 
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 ,,.,; 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. 7:18, 1 
1846 nivoriundus Fitch (Chironomus), Winter Insects of Hastern 
New York nec Orthocladius 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 
aberrata 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 broad, the 14th 
