144 TERTIARY INSECTS OF NORTH AMERICA. 



type ; it agrees better with it than JE. constricta does with any other hving- 

 form. The nodal sector of JE. sohda is not so strongly curved as in JE. 

 constricta, and the pterostigma of the fossil is slightly longer ; these are the 

 most important distinctions that were noted. 

 Florissant. One specimen, No. 8347. 



2. Subgenus Basijsschna Selys. 



As was stated in tlie general remarks under ^Eschnina, Goss's unnamed 

 ^Eschnid from Bornemoutli, England, probably belongs to this group ; an 

 interesting fact since, so far as I know, it is exclusively an American group, 

 and one of our own fossils falls therein. It is the only subgenus of ^schna 

 besides ^Eschna proper which is known in a fossil state. 



tEschna (Basi.eschna) separata. 

 PI. 13, Fig. 15. 



A complete front wing and its reverse broken near the course of the 

 median sector and the part below crowded up against the upper portion, so 

 as to confuse the parts next the line of fracture. 



The wing is of I'ather small size, rather slender and straiglit ; the tip 

 is slightly angulated rather below the middle of the wing ; nodulus placed 

 at almost two-thirds the distance from the base to the pterostigma, scarcely 

 directed backward above the subcostal, below that straiglit, directed some- 

 what forward and reaching the subnodal ; nodal sector curved rather 

 strongly and somewhat rapidly upward in the middle part of its course, 

 terminating a little distance below the tip of the wing; subnodal sector 

 simple and beyond the base of the pterostigma subparallel to the nodal ; 

 the intercalated sector between the subnodal and the median simple, 

 but curved in the course of what would be the superior fork if it were 

 branched, and even more strongly curved than in .^schna solida ; median 

 and short sectors separated apically by a double row of cells, but to how 

 far from the margin can not be seen ; in the discoidal field below tlie tri- 

 angle there are at first two, then three, and afterwards four or five rows of 

 cells, the last arranged in somewhat obscure oblique series. Pterostigma 

 five times as long as broad, botli outer and inner margin very oblique, but 

 the outer much more so than the inner ; the color uniform pale clay brown, 

 but the thickened bordering veins black. Antecubitals twenty-three, post- 

 cubitals thirteen. 



