Vol. XXviii] ENTOMOLOGICAL NEWS 175 



ping off upon a slight disturbance, whereas the ova of the 

 Corixidae are attached exceedingly firmly." 



In 1902 Mr. J. R. de la Torre Bueno called attention to the 

 fact that N. iindulata female does not make a slit in the epi- 

 dermis of the leaf or stem, but merely glues the eggs along 

 the sides in a rather irregular fashion on the surface. In his 

 paper on "The Genus Notonecta in America, North of Mex- 

 ica, 1905," he states that out of some 1300 or 1400 ova of 

 four or five species observed, in all but one instance* were 

 the eggs attached to submerged plants or twigs. 



Christine Essenberg (1915), in her studies on the habits 

 and natural history of the back-swimmers, reports that the 

 four species with which she worked at Berkeley, California, 

 namely, Notonecta undulata var. charon, N. insulata, Kirby, 

 A'^. indica and an undescribed species, all attach their eggs 

 to the stems of plants, as noted by Mr. Torre Bueno, and even 

 to the backs of other insects, such as dragon fly nymphs. It 

 would seem probable then that in the case of all of our Ameri- 

 can species of this genus, the eggs as a rule are attached to the 

 surface of their support. 



Thus a diversity in habits of oviposition between the com- 

 mon European form, as reported by Regimbart, and our own 

 species has been a matter of some interest, and it may add a 

 trifle to our appreciation of the American back-swimmers to 

 note that among them in the genus Biienoa is one which, with 

 more parental concern than is evinced by even the European 

 glauca, embeds its ova in the stems of water plants. 



At this point it may be well to recall that there are three 

 genera of the family Notoncctidae in America north of Mex- 

 ico. They are Notonecta, Bitenoa and Plea, which are repre- 

 sented by 12, 3 and i species, respectively. These may be sep- 

 arated by the following table, wherein is included a key to the 

 species of the genus Buenoa.f 



A. Legs all similar Plea Leach. 



A.A. Legs dissimilar, hind legs flattened and fringed for swimming. 



*This one instance was a case of N. undulata female which placed 

 her ova qnite deeply in the stem of a water weed. 

 fAdapted from Bueno (1905) and (1909) and earlier workers. 



