440 GEOLOGICAL SURVEY OF THE TERRITORIES. 



will stand as distinct, and its relation to the others may be represented 

 as follows : 



A. Anterior tibioe spiced in front : 



a. ProsterDum spined. fTIiyreonotus^ Pterole^ns =zz EJiacocleis, OrcJies- 



ileus.) 



aa. Prosternuni not spined : 



1), Pronotum distinctly carined 5 anterior tibit^ with three or 



four spines in front Becticus, (prop.) 



1)1), Pronotum with sub-distinct lateral carinas 5 anterior tibii^ 

 with three spines in front; elytra not squamieform.' 



Sub-genus Flataclcis. 



hhl). Pronotum without distinct lateral carinte ; elytra squamie- 

 form : 

 c. Anterior tibia3 with but three or four spines in front ; 



one row Thamnotrizon. 



cc. Anterior tibiie with six or eight spines in front ; two 

 rows < Anahrus. 



♦ This is rather artificial, depending too much upon a minor character, 

 but will i^erhaps accord with a more thorough and natural arrangement 

 when made. I have slightly expanded Fischer's spine character of 

 Decticus. I am aware that Thamnotrizon and Anohrus have been placed 

 in different groups, and although I follow the arrangement in this 

 article, I confess 1 think the differences scarcely warrant the sei)aration. 



A. coloradiis, nov. sp. 



Eather smaller than A. sim2)lcx or ^1. jnnyurascens ; ovipositor shorter 

 and more curved upward. Abdomen with brown bands. 



Eyes small, round, the most angular portion being below. Pronotum 

 rrather short ; posterior part sub-tiicarinate, somewhat liatteiied ; apex- 

 truncate. Abdomen decticoid. Superaoal plate of the female round; 

 subanal plate sub-quadrate, tumid, with a short spine at each apical angle, 

 and a short, broad spiue each side of the base. Prosternum not spined ; 

 meso- and metasteruum, with the lateral angles elevated, acute. Sui)ei'- 

 anal plate of the male somewhat acute-angled ; cerci with the two 

 prongs, mucronate, the lower ones strongly curved inward; subanal 

 plate deeply notched ; cylindrical appendages short. Legs slender, 

 short ; posterior femora with three or four minute abortive spines ou 

 the lower exterior carina. 



Color, (dried after immersion in alcohol.) — Dull yellow, varied with 

 brown. Pace yellow; occiput of the female brown; male pale. Disk of 

 the ijronotum brownish, posterior portion dark ; lower margins of the 

 sides yellow. Each abdominal segment with a brown band on the base. 

 Venter and pectus dull yellow. Elytra and wings as usual, abortive. 



Dimensions. — 9 , length, 1.28 inches; pronotum, .38 inch; posterior 

 femora, .08 inch ; i)osterior tibiae, .70 inch ; ovipositor, .73 inch. ^ , length, 

 1.12 inches. Eastern Colorado. 



LOCUSTINI.* 



* I follo^Y Walker in giviug this division, but I reduce it to a group, yet it does not 

 accord uith my opinion as to the bonudary-liues, for I really believe Thamnoirizon 

 should be placed in the same group as Bradyporus. But as I Lave not studied the 

 species of this family with suflicieut care to give a satisfactory outline of the divisions, 

 I follow those of other authors. 



