GEOLOGICAL SURVEY OF THE TEEEITORIES. 459 



indicate different species. May not two insects be exactly alike so far . 

 as external anatomy and coloration is concerned, and yet be specifically 

 diffierent ? Certainly, tbere is nothing to forbid this conclusion. Al- 

 though the perfect insects may be alike, yet the larvae or pnpee may be 

 different ; the eggs, time of hatching, habits, sounds produced, &c., may 

 indicate a difference which does not appear in the images. Specimens 

 of this species were received at the Agricultural Department during the 

 autumn of 1871, with an accompanying letter in regard to the iujuries 

 inflicted by it. The specimens I examined were communicated to me 

 by Professor Glover. 



(E. collaris, Scudd., (Hayden's Geol. Surv. Neb., 250.) 



1 did not observe this species west of the mountains, but find it among 

 my collection made in Colorado in 1869, also in the collection made by 

 Mr. Dodge in Nebraska. 



(E. tenebrosn, Scudd., (Hayden's Geol. Surv. Neb., 251.) 



Syn., Tomonotus Mexicamts, Tlios., (Proc. Acad. Nat. Sci., Plaila., 1870, 82.) 

 PI. I, fig. 2. 



Although I did not observe this species in the Salt Lake Basin, yet I 

 traced it beyond the mountains in Wyoming to the Green Eiver Valley. 

 I also find it in the collection made by Mr. Dodge in Nebraska. After 

 a thorough examination of a number of specimens, I think it is quite 

 possible that the specimens I heretofore marked T. nietanus and T. 

 pseudo-nietanus are but varieties of this species. The variations are 

 considerable in the coloration, yet I find every intermediate shading. 

 The dark border to the wings appears to be uniform and permanent, 

 being the same in all the varieties ; the flight and the shrill notes of the 

 males appear to be the samej therefore, notwithstanding the variations 

 in color and size, I am inclined to think they are all varieties of the 

 same species. 



Some of the specimens are pale ash-brown, uniformly dotted over with 

 fuscous ; others, especially the males, are nearly black ; others have the 

 entire disk of the pronotum a pale ash-yellow ; while others have only 

 the borders of the pronotum of this color. As tlie descriptions hereto- 

 fore given are from alcoholic specimens, J give the following notes from 

 my field-book in regard to the living insect : Pace pale ash, dotted over 

 very thickly with black points ; mouth whitish ; outer joints of the palpi 

 white. Wings with the broad basal portion a clear orange-red ; apex 

 transparent, marginal band of black or dark fuscous. Posterior femora 

 crossed on the outside with three pale bands, the one near the apex 

 white and straight. Upper end of the posterior tibise black, then a nar- 

 row white band, the middle portion bluish-green ; tarsi pale yellow. 

 Central portion of the sternum greenish-yellow. 



I am now inclined to think none of these varieties correspond with 

 Saussure's T. Mexicanus or T. nietanus^ but cannot say positively they 

 do not. 



(E. carlingiana, Thos., (Proc. Acad. Nat. Sci. Phila., 1870, 81 ; Haydeh's 

 Geol. Surv. Terr., 1870, 275.) 

 I saw no specimens of this species west of the mountains, but when 

 we crossed the range to the Atlantic side in Montana they again ap- 

 peared. 



