232 NEW YORK STATE MUSEitTM 



duced in long hooks, of which the outer is twice the larger and 

 each of these hooks is separated by a shallow notch from a row 

 of 5-9 minute teeth on the distal margin. There are three lateral 

 setae, tivo on the viovable hook, and one just before its base. 



Prothorax conic, tapering forward to its attachment to the 

 head. Legs very long and slender, generally faintly annulate 

 with darker color. ^ying cases narrow, elevated, their tips 

 hardly reaching the base of the fourth abdominal segment. 



Abdomen cylindric, with lateral margins becoming sharp 

 posteriorly, ending on the fourth or fifth to ninth segments in 

 minute but sharp lateral spines; segments 2-9 of about equal 

 length, 1 and 10 shorter and about equal each to the other. 

 Gills long, with parallel sides and abruptly rounded ends, dis- 

 tinctly segmented for part of their length, and generally trans- 

 Tersely banded with brown. 



KEY TO SPECIES 



Imagos^ 



a Inferior appendages of the male not longer than 

 half the superiors 

 b A large metallic gi'een species: length of hind 



wing 2.5-29 mm e u r i n a 



bb A smaller, blackish brown species: length of 



hind wing 18-22mm congener 



aa Inferior appendages of the male abdomen longer 

 than half but not longer than the supe- 

 riors 

 c Inferior appendages, viewed fi-om above, exhib- 

 iting a sigmoid curvature unguiculata 



cc Inferior appendages viewed from above, straight 

 or nearly so 

 d Metallic green species (when mature) 

 j e Inferior appendages of the male viewed 



; from above strongly dilated toward the 



apex uncata 



.^ ee Inferior appendages of the male very slen- 



A der and straight in their apical half v i g i 1 a x 



} dd Blackish brown species 



'■ f Apex of inferior appendages of male bent 



{. downward at the tip r e c t a n g u 1 a r 1 s 



( , // Apex of inferior appendages not distinctly 



^. • declined 



/ ff Inferior appendages of the male viewed 

 from above slightly widened at the tip; 

 of the two teeth on the inner edffe of 

 superior appendage, the basal one is 

 much the larger forcipata 



1 After Oalvert. Am. Eut. Soc. Trans. 1893. 20:229-32. 



