202 



Cincinnati Society of Natural History. 



and humeral stripes are narrower and darker ; the tibiae 

 yellow posteriorly instead of black ; the valves are darker, 

 relatively narrower and more hairy, the appendages are 

 slightly longer, stouter and darker, and the excavation in the 

 dorso-caudal edge of 10 has a row of ten or more comb-like 

 teeth at its angles, in Vigilax there is a cluster of a few only. 

 Inequalis is stouter. 



Oviposition appears to be conducted in a similar manner by 

 all our species. The females prefer to cling to upright 

 aquatics growing along the borders of sluggish streams or 

 ponds, where they may be concealed by the luxuriance of the 

 herbage, while they place their eggs in the stems below water. 

 That some of them, at least occasionally, descend beneath the 

 water, perhaps to the ooze at the bottom, for this purpose, is 

 pretty well established. The females of Vigilax and Inequalis 

 are often taken with bod) 7 and wings covered with silt; it 

 would seem that to immerse themselves in water and mud is 

 with them a habit. 



The remaining species of Lestes that are most surely 

 • regional are L. eurina and L. congener. 



ii. Argia putrida Hagen. 



It appears to be common everywhere. Along the shores of 

 Lake Erie and on the " Islands," in June and July, there are 

 immense numbers. Green Island is a small block of glaciated, 

 drift-covered rock, a few feet above the blue waters of Erie ; 

 it is several miles from the main land and three or more dis- 

 tant from the larger South Bass and Rattlesnake Islands; and 

 yet here, away out at sea, July 5, I found Putrida, many just 

 drying their wings, as abundant as about the borders of the 

 sheltered waters of the " Peninsula." It seems a safe con- 

 clusion that its nymphs must live in comparatively deep water 

 of the lake or cling to the algae of the wave-beaten rocks sur- 

 rounding these isolated knobs. No other species were taken 

 on this island, although several were common on South Bass 

 the same day. 



Its seasonal range I have noted as follows: May 17, Clin- 

 ton ville ; September 26, Blendon. 



