36 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



PlatypJiyma and Chromacris have probably been introduced by mis- 

 take. 



Dacfylotum has been introduced into our nomenclature for the recep- 

 tion of a very short-winged and brightly-colored species — Pezotettix 

 picta Thos. 



This leaves only the following genera as necessary to be considered : 

 Acridiumj Caloptemis, Hesperotettix and Pezotettix. 



As Hesperotettix contains, so far as we are aware, but three species, 

 easily distinguished from Caloptenus spretus by the following characters 

 and facts, it may also be excluded : One is short-winged, green, and found 

 only in the Eastern Middle States j another somewhat common in the 

 West is green, with reddish bands around the femora ; the other has 

 so far been found only in Arizona 5 it is yellow, thickly dotted over 

 with black, and the antennsB annulated with alternate colors. 



There is a difference of opinion in reference to the characters of the 

 genera Caloptenus and Pezotettix^ Professor Stal, of Sweden, maintain- 

 ing that if properly limited Caloptenus does not embrace any of our 

 species. He places C. femur -ruhrum, and consequently the closely allied 

 species, in Pezotettix. Without attempting to discuss the question so 

 far as it relates to the proper characters, we have concluded, for reasons 

 which will be mentioned further on, to retain the name Caloptenus and. 

 to use the genus in the sense understood by American and most Euro- 

 pean authors. Although the chief distinction between this genus and 

 Pezotettix, as adopted in this country, the difference in the length of the 

 wings, cannot be considered satisfactory, yet, as it will answer present 

 purposes, we will avail ourselves of it in order to eliminate the group 

 from consideration. Acridium, so far as represented in the United 

 States, may be characterized as follows : 



Vertex but slightly inclined, angularly expanded in front of the eyes; 

 anteunal grooves profound and extending downward to the clypeus ; 

 eyes elongate-elliptical. Pronotum somewhat compressed on the sides, 

 depth usually considerably more than the width, moderately but dis- 

 tinctly expanding behind the last sulcus (very slightly in rubiginosum) ; 

 lateral carinse obsolete on the anterior lobes, the sides rounding up 

 somewhat as the sides of an arch to the median carina ; the dorsum of 

 the posterior lobe more flattened, with the lateral carinse subdistinct ; 

 the lower margin of the lateral lobes straight, the posterior lateral angle 

 slightly obtuse, varying from about 100^ to llQo ; posterior margin ob- 

 tuse-angled and rounded at the tip. Elytra and wings, with one ex- 

 ception, considerably longer than the abdomen, and in the exception pass 

 it slightly. Abdomen elongate, rather slender 5 that of the male not en- 

 larged at the tip ; the last segment of the male subconical and dis- 

 tinctly notched at the tip, usually with a square notch ; cerci of the 

 male flat, usually broad, oblong, and straight. Prosternal spine,robust, 

 subcylindrical, blunt, and approximating the margin of the mesoster- 

 num. The spines of the posterior tibiae always have at least the basal 



