234 TERTIARY INSECTS OF NORTH AMERICA, 



Length of body, 25""" ; of head, 3""" ; depth of same, fi'='"' ; length of 

 tegmina, 27"""; breadth of same, 8.5"""'; of wing, 11.5""". 

 Florissant. One specimen, Nos. 4499 and 4642. 



LOCUSTARI^ sp. 



Among the Orthoptera noticed in the Green River shales is a tibia 

 and fragment of the attached femur of what is apparently the middle leg of 

 a Lociistarian about the size of a Phylloptera. 



Green River, Wyoming. No. 15233. 



Family GRYLLIDES Latreille. 



Fossil species of this family are not numerous ; only a single species 

 has been fully described from amber, and a second figured from Oeningen. 

 At Aix, however, they appear to be tolerably abundant, for Serres men- 

 tions no less than seven species, of which two are Gryllotalpa^ (Heer also 

 mentions a Gryllotalpa from Oeningen), one a Xya, while he compares the 

 four others to species of fficanthus, Gryllus, and Nemobius. Heer's Oen- 

 ingen species is probably a Nemobius and the amber species one of the 

 Trigonidii.' We have also seen a couple of species of Nemobius from Aix 

 in the hands of M. Oustalet at Paris. Our own species, three in numbei-, 

 all appear to belong in close proximity to one another and to the Gryllida3 

 pro])er, but require for their proper elucidation to be classed in a distinct 

 genus. They all come, curiously, from the Green River beds. (June, 

 18S4.) 



PRONEMOBIUS gen. nov. (;rpo, Nemobius, nom. gen.). 



Having the facies of Nemobius, but with the hind femora entirely devoid 

 of spines, or even serrulations. The species seem to differ considei'-ably in 

 certain points, but as they Jill agree in this particular, which is unique, not 

 only in this tribe, but among Gryllides generally, they are placed together. 



The species may be separated as follows : 



Table of Ihc xjiccies of Proncmohiiis. 



Hiud femora large, exceediug 10""" in length ]. P. iiidiiraliis. 



Hind femora small or medium sized, less than 8""" in length. 



Hind femora hairy 2. P. tci-tiarius. 



Hind femora smooth 3. P. sniitliii. 



' The hiud tibiie must certainly he represented as shorter than they should he, as in other respects 

 the representation appears to be that of a Cyrtoxiphns, in in-hich (as in all Trigonidii) the hind tibiis 

 are very nearly as long as or longer than the hind femora. 



