74fi 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXIX. 



!i])iciil inui'o'in. The sliohtly vaulted cul)itu.s reaches to the extreinity 

 of the apical border and j>'ive.s oti' 5 to 7 mainly simple branches to the 

 inner margin. The anal area, which is marked off by a strongly 

 curved fold, takes up two-tifths the length of the wing. The inter- 

 calary venation consists of delicate, closely crowded, undulating cross 

 veins. 



By the rounded form of the wing, the feebly branched veins, and 

 the structure of the radius, this genus is adequately characterized. 



Type of genus, 01 ethrohlatta intennedla (Goldenberg). 



OLETHROBLATTA AMERICANA, new species. 



LocaUty. — Sharp Mountain Clap, near Tremont, Pennsylvania; 

 Anthracite series; stage? 



Fig. 51.— Olethroblatta Americana. 



Length of the front wing, 17 mm. Cubitus with 5 unforked 

 branches. 



IIolotype.—Q'Ai. No. 38720, U.S.N.M. 



STYGETOBLATTA, new genus. 



Front wing about twice as long as broad, pro])abh' more kidne}^- 

 shaped. Costal area remarkabl}' Avide and extending three-fourths the 

 length of the wing, with 7 or 8 mostly simple veins. Radius forked 

 about in the middle of the wing; its superior bi'anch separated into 3 

 twigs, which continue to the anterior margin; the inferior offshoot not 

 very strongly compound, with its branches directed toward the apical 

 border. The media remains undivided beyond the middle of the wing 

 and then separates into few veinlets, which are oriented toward the tip 

 and inner margin. The cubitus with its few branches appears not 

 quite to till up the inner margin. The anal area is defined by a very 

 strongly curved fold and contains only a limited number of veins. 

 The surface of the wing appears leathery with a fin(^ gi-ain. and shows 

 no cross veins. 



A genus very well characterized b}' the broad costal area. 



