Vol. XXVlii] ENTOMOLOGICAL NEWS. 267 



The Life History of the Backswimmer, Notonecta 

 undulata Say (Hern., Het.). 



By H. B. HUNGERFORD, Cornell University. 



(Plates XIX, XX.) 



Of all our American water bugs none are more generally 

 known in their native haunts than the Backswimmers. They 

 are to be found in nearly every pool and pond and afford most 

 interesting objects for aquarium study. The fact that they 

 swim on their backs readily distinguishes them from all other 

 water bugs. 



The family Notonectidae, to which these bugs belong, is a 

 small one, there being but three genera and a total of eighteen 

 species reported for America north of Mexico. All but four 

 species are assigned to the genus Notonecta, to which our com- 

 monest forms belong. These bugs are all of fair size (8-17 mm. ) 

 and for the most part marked with black and white or with 

 black and various shades of red or brown. The various 

 species of this genus may be distinguished by the table pre- 

 pared for their identification by Mr. J. R. de la Torre Bueno 



(1905)- 



In New York State we find several interesting species in the 



same pool while in the ponds of Kansas the black and white 

 TV. undulata is the common and almost the only form taken in 

 collecting. It is the life history of this species that this paper 

 presents. 



LITERATURE. 



So far as the writer has been able to find there is no account 

 in the literature concerning the complete life history of any of 

 the species of the genus Notonecta which are often dominant 

 forms in our pools and ponds in America. Mr. J. R. de la 

 Torre Bueno (1905) in his Notonecta of North America de- 

 scribes the egg of Notonecta undulata and records having 

 reared them to the second or third instar when they died for 

 want of proper food he also presents some notes on the egg 

 stage and number of nymphal instars of N. variabilis. Chris- 

 tine Essenberg (1915) describes the egg of N. undulata and 

 gives a general account of the Notonecta egg, its incubation 



