664 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



XV. PRAIRIE DU CHIEN, WISCONSIN, JULY 25. 



Again only two species of dragonflies seen, Gom^phus externus 

 Selys, and Plathemis lydia (Drury) ; both of these were fairly com- 

 mon. The river banks were low, flat, and sandy, and in the scattered 

 weeds w^ere obtained Argia tibialis (Rambnr), A. apicalis (Say), 

 and Ischnura verticalis (Say), none of the three at all common. 



XVI. HORSESHOE LAKE, OPPOSITE McOREGOR, IOWA, .TULY 20. 



Another excellent example of colonization, Perithcmis domitia 

 (Drnry), was fonnd here by the hundreds, the males out on the lily 

 pads in the open lake, the females in the weeds along the shore. 

 This species Avas seen at only a few other places, and then only 

 sparingly. Epicordulia princeps (Hagen), and LiheUida pulchella 

 Drury were the only other dragonflies seen; the former were much 

 the more numerous and were patrolling the pickerel weed and rushes 

 along the shore. The lily pads and rushes were further tenanted by 

 three species of Enallagma, hageiil (AValsh), chrium (Hagen), and 

 signatuni (Hagen), none of them at all numerous. In addition 

 there were a few specimens of Ischnura verticalis (Say). 



XVII. WAUZEKA, WISCONSIN, .IITLY 26. 



This was 15 miles up the Wisconsin River and a half mile up the 

 Kickapoo River, on the banks of the latter. The ground was all 

 marsh land, soggy and wet, with standing water everywhere. Here 

 was found a colony of Plathemis lydia (Drury), both sexes of 

 Avhich were present in large numbers, flying about over the water. 

 The only other dragonflies seen were Gomphus externvs Selys, a 

 pair of which were captured in one of the dry spots on the marshes, 

 while others were seen flying over the water and along the flat, dry 

 banks of the Wisconsin River. There were also a few males of 

 Perithemis domitia (Drury) seen on the marshes, and Lihellula 

 pulchella Drury flying over the fields farther back from the water. 

 Of the damselflies, Hetwrina americana (Fabricius) was found along 

 the grassy banks of the Wisconsin River in limited numbers, Avhile 

 Lestes vigilax Hagen was found in the rushes on the marshes. 



XVI n. (JUTTENBURG, IOWA. .lULY 27. 



Here was a flat, dry shore, raised considerably above the water and 

 covered thickly with weeds. On it were found Lihellida luctuosa 

 Burmeister and Gomphus externus Selys, while flying about over 

 the water were Epicordulia princeps (Hagen) and a few males of 

 Perithemis domitia (Drury). Of damselflies there were found 

 Enallagma hageni (Walsh), Ischnura verticalis (Say), and Lestes 

 rectangularis Say. 



