322 TERTIARY INSECTS OF NORTH AMERICA. 



The specimen given in Fig. 5 is presumed to be a hind wing belonging 

 to this species, but is so folded that the course of the neuration can hardly 

 be determined ; if it is correctly given the hind wing must have been banded 

 like the fore wing. 



Length of body, 23.5 mm ; of head, 3.75 mm ; of thorax, 4.5 mm ; of abdo- 

 men, 15.2.") mm ; width of head 7 mm ; of clypeus, 3.8 mm ; length of rostrum, 

 8.5 mm ; width of thorax behind, 85 rani ; length of scutellum, 3 raiu ; its breadth 

 at base, 2.5 mtn ; length of tegmina, 2y.5 mm ; width next base, I0.5 mra ; near 

 tip, 8.5 mm . 



Florissant, Three specimens, Nos. 62, 411 and 412, 11241. 



2. PETROLYSTRA HERDS. 



PI. 20, Fig. 8. 

 Petrolystra heros Scudd., Bull. U. S. Geol. Geogr. Snrv. Terr., IV, 532 (1878). 



A single specimen shows one of the tegmina in a good state of preser- 

 vation, together with both fore legs. It differs from P. gigantea in the 

 broader bands of the tegmina and in the form of the latter, the posterior 

 border being slightly fuller at the base, so as to make that part of the wing 

 proportionally broader, while the posterior angle of the tip is not obliquely 

 excised, making the extremity truncate rather than pointed. The bands have 

 expanded so as to occupy the larger part of the wing ; the basal spot occu- 

 pies the entire base from border to border (excepting the very root) as far 

 as an oblique transverse line, subparallel to the inner basal edge of the 

 wing, and distant from the root nearly half the width of the wing ; it also 

 infringes upon that bordering line by a large semicircular excision in the 

 middle ; the apical spot is very nearly as long as broad, and stops just short 

 of the margin on all three sides of the apex, and in the middle of the wing 

 breaks through the intervening dark stripe into the outer of the two middle 

 hands; these two middle bands are also much broader than in the other 

 species, but not to so great a degree as the extreme bands ; they reach from 

 border to border, and are united to each other and to the basal spot along the 

 sutura clavi ; the wing therefore has the appearance rather of being pale, 

 with three transverse dark stripes, which are broad Cand the outer two 

 triangular) on the anterior half of the tegmina, narrow, sinuoua, and broken 

 i>ti the posterior halt. 



