1910] American Species of Platymetopiiis 215^ 



ceplialus. Through the former it is related to the Dorydini 

 and through the latter with the Athysanini, while with this last 

 tribe' it is independently connected by genus Scaphoideiis: I 

 still adhere to the views expressed by me many years ago as to 

 the value of the second cross nervure between the first and 

 second sectors of the elytra as a diagnostic character in the 

 Jassid genera. It is but one character among several which 

 unite a fairly homogeneous group of genera with Mesamia- 

 at one extreme and Deltocephahis at the other. The form of the 

 vertex alone can never be used for separating the Jassid genera 

 into groups nor do I know of any other single character so avail-, 

 able as is the elytral venation. That certain species of Athysaniis 

 or Eutettix show an occasional second cross nervure only proves 

 to me that those genera have but recently developed from their 

 parent stem and are still plastic. The whole group of genera 

 included by me in the Deltocephalini and Athysanini seems now 

 to, be in their ascendancy and rapidly developing in both species 

 and genera, many of which have not yet become well differ- 

 entiated. 



In the preparation of this paper I have had before me repre- 

 sentatives of all but two of the described American species, 

 modcstiis and elegans. The latter however is a distinct species 

 well known to me and it has been included in the synoptical 

 table. Of the others I have examined the types of all but 

 acutns Say, madgalensis Prov. and cinereus O. & B., the two 

 former of which certainly refer to our most abundant eastern 

 species. 



I wish here to extend my thanks to those who have, assisted 

 me with the loan of material . To Prof. Herbert Osborn I am 

 indebted for a number of his types and the opportunity of exam- 

 ining all the material in his collection and in that of the Ohio 

 State University at Columbus, Ohio; Dr. Ball has sent me his 

 very valuable material in the genus including the types of the 

 species recently described by him; and at the suggestion of 

 Prof. Baker, Dr. Howard has kindly sent me the types of the 

 three Baker species described in 1900 and with them examples of 

 ten other species from the National Museum collection. In 

 addition to this my own collection contains representatives 

 of twenty species mostly in good series. From this material 

 I have found it necessary to describe as new four species and 

 one variety. 



