140 TERTIARY INSECTS OF NORTH AMERICA, 



ule or just beneatli the tirst antecubital ; the petiolatioii therefore begins at 

 this point; the basal postcostal lies midway between the two antecubitals; 

 the arculus is directly beneath the second antecubital nervule ; there are 

 eleven postcubitals ; quadrilateral with its inner side scarcely shorter than 

 its upper, the latter half as long as the lower side ; three antenodal cellules 

 below the short sector. The ultranodal originates only two cellules before 

 the pterostigma ; the nodal at scarcely less than half-way from the nodus to 

 the pterostigma ; the subnodal terminates just below the tip of the ptero- 

 stigma, the median below its middle ; the short sector, which has a zigzag 

 course in the outer fourth of the wing, terminates apparently below the 

 base of the pterostigma or scarcely short of it. 



Length of wing, 21.65""" (the extreme base is not represented in the 

 plate, although part of it is preserved) ; breadth, 4.35°"" ; distance from 

 nodus to base, 7.65°"" ; to arculus, 3.5°^" ; to center of pterostigma, 12.5'"°'. 



This species differs from the preceding principally in the longer petio- 

 lation of the wing, the arching of the base of the costa, the number of ante- 

 nodal cellules beyond the quadrilateral, and the more apical termination of 

 the upper sectors. 



Florissant. One specimen. No. 8146. 



Agrion telluris. 



PI. 13, Fig. 10. 



Two nymphs, evidently belonging to the same species, have been found, 

 and, considering the impossibility of determining to which, if any, of the 

 species of Agrionina found in the perfect state they belong, they are treated 

 as distinct, following the precedent set by Heer, and followed by others. 

 The head is full, well rounded in front, squarely truncate and a little angu- 

 lated behind, about half as broad again as long, scarcely broader than the 

 thorax ; the antennae, or such parts as are preserved, are very slender, a 

 little shorter than the head, the basal joint twice as stout, about twice as long 

 as broad. The legs are very long and slender, especially the hinder pair, 

 Avhich would reach to the base of the antepenultimate abdominal joint ; the 

 femora are narrowly and equidistantly four times barred with dark bands, 

 the extreme bands at base and apex ; the tibiae are less than half as broad 

 as the femora and have a broader median dusky band. The dark wing pads 

 are long and slender, twice as long as the widtli of the abdomen, and less 



