144 journal New York Entomological Society. [Vol. xm. 



the Notonectce likewise destroy such as are sufficiently small to be 

 overcome by them ? I have seen nymphs of Notonecta undulata Say 

 in the second instar kill and suck the juices of young fish which had 

 just emerged from the egg in my aquaria. Prof. S. A. Forbes's two 

 papers on the food of fresh-water fishes, in the Bulletin of the Illinois 

 State Laboratory of Natural History* show that they are of very little 

 account as fish food. He says ( /. c.~) ; "Indeed, the true Waterbugs 

 (Hemiptera) were generally rare, with the exception of the small 

 soft-bodied genus Corixa, which was taken by one hundred and ten 

 specimens, belonging to twenty-seven species — most abundantly by 

 the sunfishes and top-minnows." Further on in the paper he tabu- 

 lates the families, and in some instances, species, of insect fich-food, 

 and contrasting with the number of fish above mentioned that ate 

 Corixas, only one fish was found to have fed on Notonectas, out of the 

 entire number examined. 



Because of their apparent lack of economic importance, the knowl- 

 edge of American forms is very imperfect and but scant information 

 is available regarding their distribution, habits, life-history and anat- 

 omy. This I have found at every turn while consulting authorities. 

 For this reason in the following pages I will endeavor to make it pos- 

 sible for anyone to identify with very little trouble any of the species 

 of the genus Notonecta that occurs north of Mexico ; and by thus facil- 

 itating this identification and by pointing out gaps in our knowledge 

 that might readily be filled, especially in distribution, induce others 

 to collect and study a group which I am certain will be found eventu- 

 ally to be of positive economic importance, not only as an enemy in 

 fish-culture, but possibly also in useful ways by the destruction of 

 undesirable aquatic larvae. The figures illustrating the various species 

 will enhance the value of this paper, being true to nature and showing 

 very perfectly the different physical characteristics of the waterbugs, 

 being drawn to scale and in perfect proportion. They are the work 

 of Mrs. William Beutenmiiller, who is, I consider, one of our foremost 

 insect artists. I here wish to express my appreciation of her great 

 kindness in consenting to make these drawings. 



The genus Notonecta Linne is of world-wide distribution, but ap- 

 pears to be more especially an American group. Of its twenty species 



* -'Studies on the Food of Fresh Water Fishes, - ' Art. VII, Vol. II. "On the 

 Food Relations of Fresh Water Fishes : A Summary and a Discussion," Art. VIII, 

 Vol. EI. 



