MAY FLIES AND MIDGES OP NEW YORK 117 



All the known species of Corynoneura are extremely minute. 

 In the original diagnosis the number of the segments was said to 

 be five; they were enumerated from below, and the proximal seg- 

 ment was taken to be metathoracic. 



The foregoing description is taken from VerralPs article in 

 Phil. Trans, of the Royal Soc. of London, vol. 168, p.246. The 

 figures on pl.37 are also copied from Verrall. No North American 

 species. 



Genus 13. Psamathiomyia Deby 

 Journ. Royl. Micr. Soc. ISO. 1889. (P1.35, figs. 4 to 9) 



This genus was erected for a small Dipteron found in abund- 

 ance during the latter days of April, 1888, at Biarritz in the 

 south of France. The following is an abstract of Mr Deby's 

 paper: 



Psamathiomyia pectinata is a marine insect, living 

 below water during its early existence, the larva feeding on 

 Enteromorpha. The adult escapes from the pupal case 

 while the descending tide has laid bare the algae covered rocks ; 

 these small insects swarm at such times, being especially active 

 when the sun shines on them. The males are more numerous than 

 the females, and are also much more rapid in their motions. . . . 

 Both sexes have rudimentary wings, quite useless as organs of 

 ight. so that these insects cannot possibly escape from the 

 rising tide, which on this coast is accompanied by heavy surf 

 and breakers. It is presumed that the life of the imago does not 

 exceed the few hours during which the tide has receded. Several 

 specimens which were immerged in a vial of sea water were 

 immediately drowned. These insects fbeing small have to be 

 looked for with attention, but once discovered they are easily 

 recognized; the iblack,^very long-legged males look like minute 

 spiders, while the dingy brown louse-like females, which they 

 drag after them, have the appearance, from a distance, of the 

 cocoons some spiders carry behind them. 



Generic characters. Antennae (fig.6) six- jointed in both sexes, 

 three middle joints submoniliform, neither feathered nor plumed, 

 much shorter than the thorax and head; mesonotum (fig.9) cucul- 

 late, projecting over the head; legs very long and slender, 

 especially in the males, the terminal joint of the tarsus being 



