». 1692. DRA00NFLIE8 OF THE MISSISSIPPI VALLEY— WILSON. QQ^ 



Here were found large numbers of Libellula pulchella Drury with 

 Plathemis lydia (Drury) and a species of Macromia. 



Along the river bank pulchella was not as numerous, and there were 

 associated with it Erythemis simplicicollis (Say), Pachydiplax longi- 

 pennis (Burmeister) , Macromia tceniolata Rambur, Gomphus vastus 

 Walsh, G. notatus Rambur, two species of Hetcerina^ one of which 

 was americana (Fabricius), Argia tibialis (Rambur), Argia violacea 

 (Hagen), and a species of Aiiax., of which none could be obtained. 



SUMMARY. 



Certain facts must be kept in mind while endeavoring to summarize 

 these observations. 



1. With few exceptions the examination of each locality was con- 

 fined to a period of only a few hours duration. Hence the species 

 obtained would represent the fauna of the locality for that day only, 

 and would give but few suggestions in reference to its fauna at other 

 times, or to seasonal changes. 



2. The dates for each of the localities examined were different. 

 While this would have little practical influence for neighboring locali- 

 ties visited within a few days of each other, it would mean a great 

 deal when the interval was increased to a month, (5r even two months. 



3. There was a continual progress in the localities visited from 

 Minnesota, one of the extreme Northern States, to Alabama, one of 

 the extreme Southern. Hence the geographic changes would' cause 

 considerable differences in the fauna, irrespective of the seasonal 

 changes, and by thus combining the two their separate influence 

 would be much augmented. 



In spite of these difficulties, however, there are certain conclu- 

 sions which may be fairly drawn from the observations which have 

 just been recorded. 



1. A small fresh-water lake or pond, surrounded by shrubbery 

 and vegetation, furnishes the ideal breeding place for dragonflies and 

 damselflies, with which even such a river as the Mississippi, with 

 its numerous sloughs and bayous, is scarcely worthy of comparison. 

 The larvae of these insects evidently prefer clean to muddy water as a 

 medium in which to live; in witness whereof may be cited the fact 

 that not a solitary specimen of the Neuroptera was seen on the Mis- 

 souri River or on the Mississippi between the mouth of the Missouri 

 and the mouth of the Ohio. 



2. Only a single species was found in all the localities visited. 

 This species, Lihellula pulchella Drury, may therefore be taken as the 

 most widely distributed in the Mississippi Valley, both geographically 

 and seasonally. A close second was furnished by Pachydiplax longi- 

 pennis (Burmeister), which appeared in nearly all the localities. 

 Furthermore, neither of these species was found colonized anywhere. 



