232 TEliTIARY INSECTS OF NORTfl AMERICA. 



Leng-th of body, S ;U""", ? 28'"""; of teg-niina, 2 29""": of hind femur, 

 c?23"""; of ovipositor, 16"'"'; breadth of latter in middle, 1.1""". 



Florissant. Two specimens, Nos. 13551 (jf), 7748 and 13550 (?). 



LOCUSTA Linne. 



This genus, which occurs in the Old and New Worlds alike, but in the 

 New World only in the western portion of our countr}", has never before 

 been found fossil, several species referred to Locusta belonging elsewhere. 

 Locusta groenlandica, as stated, is probably one of the Pseudophyllidfe, and 

 the Locusta mentioned by Serres as found at Aix is, to judge from his ref- 

 erence, one of the Decticida\ A single form has been found at Florissant 

 not unlike the living species. (July, 1884.) 



Locusta silens. 

 PI. 17, Figs. 9, 10. 



A single specimen showing the base of the abdomen, with a side view 

 of the folded wings and tegmina and a portion of the hind femur, indicates 

 a species of true Locusta about as large as L. occidentalis Thorn, from Cali- 

 fornia. The arrangement of the veins in the tegmina, thoiigh confused bv 

 the overlapping of the wings, is nevertheless distinctly that of Locusta proper; 

 this does not appear in the plate, where the mediastinal and internomedian 

 nervules are not shown, and the scapular vein made to do duty as the costal 

 margin. The wings were apparently obscurel}^ griseons and perhaps longi- 

 tudinally streaked as in the recent species mentioned. The hind femora 

 were slender just as in Locusta, but along tlie middle of the outer face in 

 the thickest portion is a distinct though very delicate carina showing in 

 some parts, as in Fig. 9, a very delicate spinulation. The modern species 

 mentioned has no mid-lateral carina. 



Length of tegmina, 42""' ; width of same, 7'°™ ; probable length of hind 

 femora, 32™"'; width of same, 3.5""'". 



Florissant. One specimen, No. 7544. 



Subfamily GRYLLACRIDID.^ Stal. 



This family has been supposed to have a great antiquity, but this may 



be doubted, since I have sliown elsewhere that several of the species from 



Carboniferous deposits referred here belong rather to the neuropteroid series. 



We find, liowever, several Tertiary species referred here, two from Radoboj, 



