426 The University Science Bulletin. 



has worked against there being a very large number of students 

 who have found the time and inclination to identify the species in 

 such families as the Notonectidse, Nepida? and Corixidse, for in- 

 stance. 



The difhculty encountered by the writer in sorting and naming 

 the aciuatic bugs in the course of his biological studies led to a thor- 

 ough investigation for diagnostic characters of more demonstrable 

 kind than those employed in the literature. It has been the en- 

 deavor, therefore, to find and figure characters of sucli definiteness 

 that anyone with even fair training in close work can be certain of 

 the species he is trying to identify. 



The first report upon this work was given under the title, "The 

 Male Genitalia as Characters of Specific Value in Certain Crypto- 

 cerata," which appeared in volume XI of the Kansas University 

 Science Bulletin, December, 1919. In this the writer called at- 

 tention to these characters in the Naucoridse, Saldidae (not a crypto- 

 cerate, of course), Gelastocoridae, Corixidse and Notonectidse. The 

 treatment of the genus Notonecta was sufficiently complete to be of 

 value to the systematist, because the male genital capsules of all the 

 North American species were figured or described, save two, A\ iM- 

 eri Kirk, and N. montezuma Kirk., the former readily recognizable 

 by the description, and the latter exceedingly rare, repre.>:nted, so 

 far as indicated in the literature, by two specimens in the Hope 

 museum, carefully studied and figured by Champion. (Figure 8, 

 plate XXXI, Science Bulletin XI, figures Notonecta howarclii Bueno, 

 and fig. 5, plate XXXI, Science Bulletin XI, figures Notonecta 

 shooteriiVhl. The one there named N. lutea is, of course, N. borealis 

 Hussey and Bueno.) 



Studies were made upon the Nepidse and Corixidae, but were not 

 reported in the first paper, and there was no intention, until recently, 

 of publishing upon the Nepidse. However, four species of Ranatra 

 have been taken in Kansas waters as a result of recent collecting, 

 all new records for the state. The task of naming these water scor- 

 pions involves problems in nomenclature and the authenticity of 

 species — matters concerning which there is a difference of opinion 

 among our best authorities. 



Mr. J. R. de la Torre Bueno has believed that Ranatra nigra Her- 

 rich Schaffer 1853, is a synonym of Ranatra fusca Palisot Beauvois 

 1805. The insect which he calls Ranatra fmca is large with very 

 prominent eyes, slender anterior legs, and a deep, broad prosternal 

 groove — a very characteristic insect. With this interpretation of 



