OF WASHINGTON. 37 



though the larva has been frequently alluded to it has, up to 

 the present, remained uncharacterized. A few larvae of this 

 form were taken by the writer at Urbana, 111., on October 2, 

 1904, in a temporary puddle, where they were associated with 

 numerous larvae of Culex pipiens and a few of Culiseta conso- 

 brimis. In confinement the larvae of Sayomyia preyed upon 

 the young larvae of Culex, and from one that pupated the 

 imago was disclosed October 10. 



The larva of this small species resembles very much the 

 larvae of the other species of Sayomyia in general appearance. 

 When the larva apprehends danger it sinks slowly to the 

 bottom, maintaining throughout its horizontal position. The 

 writer has also observed this maneuver in the larvae of other 

 species of the genus and in those of Caret lira (Mochlonyx). 

 Dr. Fr. Meinert, in his work " De eucephale Myggelarver," 

 has already noted this action of the larva, without, however, 

 offering any explanation of the manner in which it is ac- 

 complished. When suddenly disturbed the larva changes its 

 position very rapidly by a switching motion in which the two 

 extremities are brought nearly together. 



A few more larvae of the present species were obtained on 

 Nov. 8 when dipping for Culex larvae in Salt Fork, a small 

 stream on the outskirts of Urbana. In February, 1905, more 

 larvae were obtained by some university students from a pond 

 known as Crystal Lake, formed by the damming of the above 

 mentioned stream. When a hole was cut through the ice 

 these larvae rose to the surface. 



This species is the " Corethra larva " alluded to by Dr. S. 

 A. Forbes in several of his writings, as the writer ascertained 

 by an examination of the material in the collection of the 

 Illinois State Laboratory of Natural History. From the data 

 accompanying this material it appears that the larva of this 

 species frequents the open water of lakes and rivers. Two 

 plankton hauls from the Illinois River in mid-stream at Ha- 

 vana, 111., August 12 and October 14, 1896, contain specimens 

 of this larva. Other specimens, from Cedar Lake, 111., taken 

 October 23, 1882, are those referred to by Doctor Forbes in 

 his articles, " Leptodora in America " (Amer. Naturalist, 1886, 

 p. 1057) and "The Lake as a Microcosm" (Bui. Peoria Sci. 

 Assn., reprint, 1887, p. 8). 



Although closely similar to other species, the larva of 

 Sayomyia punctipennis possesses distinctive characters in the 

 form of the leaf-like appendages of the ventral surface of 

 the head and in other structural details. Behind the eighth 

 abdominal segment a pointed hood-like flap projects back- 



