300 TERTIARY INSECTS OF NORTH AMERICA. 



This genus reminds one of the South American genus Alcestis Stal, but 

 differs decidedly from it in the form of the tegmina, the absence of obhque 

 inferior ramuli to the inner uhiar vein, the course of the anal veins, and the 

 structure of the head. 



Table of the species of Lithopsia. 



Tegmina less than three times as long as broad 1. L. fimbriata. 



Tegniiua more than three times as long as broad 2. L. elongata. 



1. LiTHOPSIS FIMBRIATA. 

 PI. G, Figs. 36, 37. 



Lithopsis fimbriata Scudd., Bull. U. S. Geol. Geogr. Snrv. Terr., IV, 774 (1878) ; in Zlttel, Handb. d. 



Paheont., I, ii, 781, Fig. 989 (1885). 



A tolerably well-preserved specimen, with its reverse, together with 

 the fragment of a wing, are the principal basis for this species. The vertex 

 between the eyes is more than twice the width of the eyes, and is marked by a 

 slight, median, longitudinal carina; the front of the vertex is nearly straight, 

 does not protrude beyond the eyes, but is retracted next them, making it very 

 broadly convex. The thorax is considerably broader than the head, but the 

 condition of the specimens does not allow a more definite statement. The 

 tegmina are the best preserved remains of the animal, being perfect, although 

 somewhat obscure, partly from the veins of the underl3'ing wings ; they are 

 more than two and a half times longer than broad; the costal margin, 

 especially its basal half, moderately curved, the commissural margin almost 

 ])erfectly straight, the apex slightly and obliquely subtruncate, so as to 

 throw its well-rounded apex below the middle ; near its extremity the mar- 

 gino-costal field occupies more than a third of the breadth of the tegmina, 

 being double its width near the base ; the first branching of the inner ulnar 

 vein is as far from the apex of the tegmina as the second branching is from 

 the base ; and the third branching, where, and where only, the longitudinal 

 veins are united by cross-nervures, is midway between the second branching 

 and the apex ; close to the apical margin there is an inconspicuous fourth 

 series of furcations. 



Length of body, 9™'"; of tegmina, 9 75°""; breadth of the same in the 

 middle, 3.65"""; next the third branching of the longitudinal veins, 3.25""'. 



Green River, Wyoming. Three specimens, Nos. 143" (F. C. A. Rich- 

 ardson), 4185 and 4189 (S. H. Scudder), 118 (Dr. A. S. Packard). 



