434 NEW YORK STATE MUSEUM 



€ies Yellowish iu color, often colorless; the larger oues often a 

 deep red. All Chironomns larYae build a cylindrical, gelatinous, 

 or silky case, in which they usually are hidden. The larYae of 

 Tanypus possess a distinctly segmented, somewhat flattened 

 body, with long conical anal prolegs, an elongate triangular 

 head, with distinct eye spots. They do not appear to build a 

 larYal case." Those Oeratopogon which in the adult state do not 

 possess hairy wings, haYe aquatic larYae. These are Yery elon- 

 gate, snakelike in form, with a conical head, no thoracic or 

 oaudal appendages. saYC sometimes a few bristles at the tip of 

 the last segment. 



The pupa of Chironomus usually lies hidden in the larYal case, 

 keeping the water surrounding it in circulation by the undulat- 

 ing motion'of the abdomen. The pupa of Tanypus is actiYe and 

 resembles that of Culex. The pupa of Ceratopogon is more elon- 

 gate than that of Tanypus, and is not actiYO, but floats nearly 

 motionless, with its body in a Yertical position. 



For determining the genera of the imagos, the table given 

 by Williston in his Manual of flic Xorth American Diptcra is most 



useful. 



Chironomus (sens, str.) sp. 

 Plate 49 

 A large number of larYae and pupae were taken from the 

 stomachs of brook trout, as has been described by Professor 

 Needham in this bulletin. Many specimens were examined and 

 all found to belong to the same species. The species evidently 

 being of great importance as fish' food, it is desirable that it may 

 in the future be recognized, and therefore I herewith describe 

 it. Many characters here giYcn apply to the genus as well. 



Body slender, 12 segmented, full grown specimens about 18mm 

 in length. Occasionally, still liYing specimens were found 

 within the fish stomachs; these possessed the brilliant red color 

 no characteristic of certain Chironomid larvae. At the anterior 

 end of the first segment and at the posterior end of the 12.th 

 are pains of prolegs. The head is small, dark brown, heavily 

 chitinized, a little longer than wide. The sclerites of the head 

 consist of a dorsal, ventral and two lateral plates, besides a 

 number of smaller ones. The dorsal sclerite resembles that 

 shown on plate 50, figure 4; but there are three pairs of bristles 



