14 DRAGONFLIES OF OHIO. 



stigma white. Abdominal dorsum with green and 

 pale and interrupted apical yellow rings on 2-7 ; ten 

 with a dorsal carina and apical thorn; appendages 

 conical pointed ; valves short, dark. 



This very handsome species occurs along the Ohio 

 river and ascends the larger streams as far as the 

 central district. It is not rare, but far less abundant in 

 its range than americana. It flies much more rapidly 

 than the other, otherwise its habits appear to be 

 similar. It prefers the borders of streams where the 

 flow is rapid. 



THE SECOND SUB-FAMILY. 



AGRIONIN^. 



This group includes the smallest dragonflies, in fact 

 all Ohio species are small. Not so in tropical America, 

 where representatives are known that are the most 

 gigantic of living odonates. 



Our feebler inhabitants of the river bottoms may be 

 seen in numbers on any warm summer day flitting 

 among the sedges of the shallows or busy placing their 

 eggs among floating aquatics. They are not seen 

 flying high in the air or patrolling the beach in search 

 of mates or food, for they seek their kind and prey in 

 the low thickets of aquatic foliage. Many are dull in 

 color, many are brilliant; green, blue and yellow are 

 favorite colors. All are graceful and charming. 



The genera may be outlined and limited by the following syn- 

 optically arranged characters: 



1. Median and submedian sectors arising nearer the arculus than 



the nodus Lestes. 



Median and submedian sectors arising near the nodus 2. 



2. Bristles on the legs, long, — each about twice as long as the 



distance from the base of one to the next Argia. 



Bristles on the legs shorter 3. 



3. No ventral spine at end of 8 in the female 4. 



A ventral spine at end of 8 in female 5. 



