434 The University Science Bulletin. 



Hemipterologiques de I'Europe et de I'Amerique du Nord" (Pro- 

 ceedings of the Seventh International Zoological Congress, 1907), 

 lists the genus Ranatra as belonging to the oriental fauna. Since 

 that time Doctor Montandon has added several names to our Ameri- 

 can lists. 



The species in the genus are superficially so similar in color and 

 general characteristics that there has been much confusion in 

 naming them. The descriptions have been made in several cases 

 from a single specimen, without, therefore, a consideration of varia- 

 tions within the species. They have dealt with comparisons that 

 can be appreciated only after long familiarity with the insects, and 

 on this account many errors of determination have arisen. The 

 most unfortunate circumstances attending the study of North 

 American Ranatra has been the failure to recognize the identity of 

 Ranatra jusca P. B. 1805 and Ranatra nigra H. S. 1853, the de- 

 scriptions of which are inadequate, and therefore, since the types are 

 not available, can be interpreted authoritatively only through the 

 examination of abundant and representative material from the 

 entire country. 



After studying long series of specimens representing a wide dis- 

 tribution, the writer has been compelled by the evidence before him 

 to place a new interpretation upon our North American Ranatra. 

 This lie has been reluctant to do, because it involves the renaming 

 of our commonest two species. Stability, however, can never be 

 attained in this group by postponing or ignoring the evidence that 

 eventually must prevail. 



Ranatra jusca P. B. was described and figured in color, natural 

 size, by Palisot de Beauvois, in his 'Tnsectes recueillis en Afrique et 

 in Amerique, dans les Royaumes d'6ware et de Benin,a Saint Domin- 

 que et dans les Etats Unis, pendant les annees 1786-1797." 



The figure is not amplified nor enlarged as suggested by Doctor 

 Montandon (Bulletin Soc. Sci. Bucharest, vol. XIX, 1910), who was 

 in error in endeavoring to make R. kirkaldyi Bueno, our smallest 

 North American Ranatra, fit a drawing that has the dimensions of 

 our largest species. He was mistaken in believing R. kirkaldyi 

 Bueno a synonym of R. jusca P. B., for there are two convincing 

 reasons for believing R. jusca P. B. is represented natural size. 



First. Palisot de Beauvois in his "Discours Preliminaire," page 

 XV, says, "J'ai adopte, pour la grandeKur des figures, un plan uni- 

 forme, et qui m'a semble'plus commode, c'est-a-dire,celle d'un pouce 

 pour tous les Insectes plu^ petits que cette mesure adoptee, en plac- 



