566 TERTIARY INSECTS OF NORTH AMERICA. 



Family STRATIOMYID^E Leach. 

 LITHOPHYSA gen. nov. {Xido?, <pvGa). 



This genus, of the section Beridina, is peculiar for the plump, ovate 

 abdomen, somewhat as in Diphysa, for having no lower intercalary vein, for 

 the distance at which the lower branch of the fourth longitudinal vein arises 

 from the apex of the discoidal cell and for the presence of six spines on the 

 metanotum. 



The head is large and nearly as broad as the stout oval thorax, the eyes 

 occupying above all but a narrow mesial belt about a fifth the width of the 

 head; the antenna3 apparently as in Xenomorpha, shcirt and tapering regu- 

 larly apically. Tlie metanotum has six coarse, equidistant, and not very 

 long spines, the middle pair a little stouter than tlie lateral. The auxiliary 

 vein terminates a little beyond the middle of the wing, and a little beyond, 

 like the first and second longitudinal, it curves upward rather strong]}^ at the 

 extremity. The third longitudinal vein is forked. The basal cells are of 

 equal length and half as long as the wing ; the discoidal cell about twice as 

 long as broad, two branches issuing from the two outer angles and the third 

 branch from the lower border close to the second basal cell. Abdomen 

 regularly ovate, broader than the thorax, composed of six visible segments, 

 besides, probably, a basal segment, which the preservation of the fossil does 

 not permit to be seen. 



LiTHOPHYSA TUMULTA. 



PI. 9, Fig. 31. 



This species is represented by a single specimen which is tolerably well 

 preserved. The thorax is darker than the head and abdomen, and the ob- 

 scurity of the base of the latter leads to the presumption that it was pale in 

 life; the hinder edges of the abdominal segments are a little darker than 

 the rest of the abdomen. The wings are clear excepting the fuliginous 

 stigma which embraces the interspaces on either side of the second longi- 

 tudinal vein from where it parts from the third vein to its tip. The discoidal 

 cell is almost regularly pentagonal, and would be quite so were the lower 

 branch of the fourth longitudinal vein to arise a short distance farther toward 

 the base ; the base is outward, and the outer, upper, and lower sides are 

 longer than the inner ; it is situated about midway between the costal and 



