236 



ules on the nervures. In this as in many of our other Delphacids the extent 

 of the pale markings is quite variable in different individuals and the females 

 are proportionately broader than the males. 



Is not the large foliaceous spur in this species an adaptation of Nature 

 to enable these insects to leap more readily from the surface of the water 

 about which they make their home? 



GENUS PISSONOTUS, n gen. 



Head narrower than the pronotum ; vertex hardly prominent before the 

 eyes; front narrow above, much expanded below, the sides arcuated, median 

 carina forked about one third its length below the apex of the head, the 

 two branches subparallel closely approximated for most of their length. 

 Thorax broad across the middle, convex, narrowed anteriorly; pronotum 

 nearly straight across the hind edge, lateral carinse rather widely divergent 

 at their apex a little incurved, hardly attaining the posterior edge. 



This genus seems to be intermediate between Megamelus and Dicran- 

 otropis. P. marginatus and its allies are highly polished little insects, 

 broadest across the base of the elytra which in the brachypterous examples 

 are small, truncate behind, smooth and polished with the nervures nearly 

 obsolete, and the scutellum is unusually small. P. basalis has a large 

 scutellum and has much the appearance of a Kormus, but the lateral carina; 

 do not follow the posterior curve of the eyes and the front is much wider 

 below with its median carina distinctly forked some ways below the apex of 

 the head. P. aphidioides and its allies are dull brown insects widest across 

 the abdomen, at least in the brachypterous examples which alone are known 

 to me, giving them a strong resemblance to some of the subterranean plant- 

 lice near Rhizobius. All the species have the apex of the front pale, and a 

 broad black band crosses the dypeus and the anterior and intermediate 

 cox£e. Some of the species, especially brunneus, bear a strong resemblance 

 to members of the genus Dicranotropis, and it may be necessary to modify 

 that genus so as to include them when their winged forms are known. For 

 the present these may be distinguished by having a broader front with the 

 forks of its median carina closely approximated below the apex of the head. 

 The brachypterous forms of brunneus, aphidioides and their allies have 

 strong pale elytral nervures. 



The type of this genus is Pissonotus marginatus. 



I PISSONOTUS MARGINATUS, n. sp. 

 Van Duzee, Bui. Buf. Soc. Nat. Sci., V, p. 190, 1S94. 

 Vertex, pronotum and scutellum nearly equal in length, the former 

 almost square, hardly prominent before the eyes, the latter unusually small 

 with the edges nearly rectilinear and the apex but slightly produced. Elytra 

 short, rarely covering the second abdominal segment, cut squarely off behind, 

 almost coriaceous, shining, the nervures nearly obsolete. Abdomen of the 

 female broadly ovate, in the males more slender. Aperature of the pygofers 

 of the male rather broad, superior wall of the anal tube produced in long 

 incurved tusk-like horns that are nearly parallel and rest with their tips 

 against the indented ventral margin of the pygofers; stiles small, incon- 



