NORTH AMERICAN AUCHENORRHYNCHOUS HOMOPTBRA. 837 



as they are generally called in America), Cercopidfe, and Asira- 

 cinae (Delphacidfe) lias of late years been considerably increased, 

 chiefly through the labours of Van Duzee, Osborn, Ball, C. F. 

 Baker, C. P. Gillette, and others, to a large extent, no doubt, 

 because these insects are of some economic importance. 



Seven papers by three of these authors are now noticed, not 

 because the remaining publications during the past five years 

 are not valuable, but because those chosen are to some extent 

 monographic revisions of difticult and little-known groups. 



Van Duzee admits twelve American genera of Delphacidse,* 

 with over fifty species, which will certainly be greatly extended 

 by future workers. Of these, seven genera and four species are 

 found also in Western Europe. Osborn and Ball have furnished 

 detailed descriptions and valuable figures of Deltocephaliis, Pedi- 

 opsis, Idiocerus, Agallia (all European genera) ; while Osborn has 

 revised ScapJtoidens, a genus closely allied to Deltocephaliis, but 

 restricted to America. Ball has also reviewed the Cercopidse, 

 admitting six genera (four also West European) and sixteen 

 species. The revision of the Tettigonidae deals with Tettigonia 

 and its near allies, Gijpona being reserved for a future paper. 

 Seven genera are recorded. 



These seven papers comprehend some 270 pages, with twenty- 

 three plates, the latter embracing nearly five hundred illustra- 

 tions. In the attention paid to structural details (especially 

 of the genital segments), and in the broad and philosophical view 

 taken of " variation," the " limits of species," &c., and in the 

 general preparation of the descriptions, I have no hesitation, 

 having regard to the obscurity of most of the groups dealt with, 

 in placmg them as a whole in the very front rank of homopterous 

 publications. It may be noted, as some proof of the interest 

 taken in the Homopt'era, that these authors have criticised and 

 recriticised one another's writings very freely in the pages of 

 ' Psyche,' ' The Entomological News,' and other publications. 



Having regard to the fact that not only a number of genera, 

 but even of species, of the Homoptera are common to America 

 and Europe, the descriptions and detailed figures cannot but be 

 useful to British entomologists. The papers are elucidated by 

 copious analytical tables of genera and species ; but though the 

 black illustrations appear to be carefully drawn, coloured figures 

 of some at least of the remarkable variations mentioned would 

 have perhaps enhanced their value. There are many valuable 

 observations and notes on the habits and metamorphoses pf 

 American Homoptera, which will be summarized later on in 

 another paper. 



The following is a list of the Auchenorrhyncha common to 

 North America and Western Europe ; it is probably incomplete 



- The nomenclature of the several authors is employed to prevent 

 confusion. 



