158 The Ohio Journal of Science [Vol. XXI, No. 5, 



Suborder Zygoptera.* 



Family Agrio7iidcE. 



Argia violacea (Hagen). Nymphs of this species, unlike 

 others of the Argias, and more like Lestes and Enallagma, 

 could have been expected in good number in the small pond, 

 for conditions there were ideal. "It oviposits" (Needham '03) 

 "commonly in mats of algae at the edge of the water or covering 

 floating vegetation." Nymphs were rather few, all found in 

 September, while the adults, not numerous either, were taken 

 in the early half of summer. 



Enallagma antennatum (Say). These nymphs were the 

 most numerous in the pond ; the species can certainly be listed 

 as common. But as for adults only a very few were of this 

 species. The discrepancy was largely due to the peculiar flight 

 of this species close to the water line and directly through the 

 shore vegetation (Needham '03), whence they were unwittingly 

 overlooked while collecting more conspicuous fliers. 



Enallagma exsulans (Hagen). This species was rare. Only 

 one nymph and no adults were obtained. 



Ischnura posita (Hagen). This species was less common 

 than E. antennatum. Nymphs were most common early in the 

 season. Adults were scarce at the time collections were made. 



Ischnura verticalis (Say). This was a very common species 

 and possibly it was more abundant than E. antennatum or at 

 least equally common. Fewer nymphs but many more adults 

 of this species were secured. 



Suborder Anisoptera.f 



Family Lihelliilidce. 



Libellula pulchella Drury. This was the commonest of the 

 dragonflies. Adults were noticed often during the summer, 

 and nymphs, though not numerous compared with the com- 

 monest damsel fly nymphs, were more numerous than all 

 others of the suborder put together. With one exception all 

 nymphs were from the small pond. 



Libellula basalis Say was common about the pond but no 

 nymphs whatever were secured. 



*^ Figures in table are of the nymphs collected that were identified. This 

 excludes a very large number of small nymphs. Since adults were not collected 

 at these definite stations, they are omitted from the numbers given in the table. 



t Figures in the table are of the collected nymphs which were identified, 

 except that Pachydiplax (represented by only one adult) is added. 



