KELLICOTT. 51 



quiet nook among the weeds or in other species far out 

 on the rough surface of swift stream or wind disturbed 

 lake. Most species fly in early summer, some in mid, 

 and a few late in summer. 



The genera represented may be defined and sep- 

 arated as follows : 



I. 



Median lobe of the labium bifid. 



A. Basilar space free; triangles of front wings crossed; 

 females with genital valves. (Legion, Petaluria, Selys. ) 



1. Triangles of the front wings with the upper side longer than the 

 inner, outer longest ; superior appendages of the male much 

 widened beyond the middle; pterostigma ver3' long, Tachopteryx. 

 ( Not yet taken in the state, j 



II. 



Median lobial lobe entire. 



Basilar space free; female without genital lobes. 



B. A part or all of the triangles crossed, membranule 

 small or wanting. (Legion Gomphoides, Selys). 



1. Legs long, hind femora reaching to the apex of 2 ; triangles 

 crossed ; internal and supra triangular spaces free Hagenius. 



C. Triangles and supratrianuler spaces free; membran- 

 ule very small or wanting. (Legion Gomphus Selys). 



1. Inferior appendages bifid, branches nearly contiguous, straight, 

 up-curved at apex Ophiogompbus. 



2. Inferior appendages of the male bifid, branches divergent ; super- 

 iors but little longer than 10, divergent. Vulvar lamina con- 

 siderably shorter than 9. 



(1). Hind femora of moderate length with many short spines, 



Gomphus. 



( 2 ). Hind femora long ( reaching apex of 2 ) spines many with 

 an inferior row of 5-7. Much longer than the rest, 



Dromogomphus. 



HAGENIUS, Selys. 



There is only one known species in North America ; 

 this is fairly common, at least in Northern Ohio. It 

 prefers the borders of sluggish streams and bayous. 



