REHN AND HEBARD ICo 



G. Coloration not as brilliant. Convex callosity of lateral lobes 

 very narrow and subobsolete. Cerci of similar type to those 

 of nigropleurum but longer though but little more slender, with 

 distal portion curved outward. Ventro-external margins of 

 caudal femora bearing nornialh' two and two spines. 



attenuatus (Scudder) 

 GG. Coloration very brilliant. Convex caUo.sity of lateral 

 lobes moderately but not decidedly broad. Cerci of similar 

 type to those of nigropleurum but much more slender, with en- 

 larged portion and distal portion both more attenuate, slightly 

 irregular in outUne. Ventro-external margins of caudal femora 

 in much more than half of the examples unarmed, when 

 spines are present these range from one to two. 



nigropleuroides (H. Fox) 

 EE. Vertex with greatest width two-thirds that of proximal antennal 

 joint. Eyes normal. (Coloration not striking, resembling that of 

 aigialus but with the j-ellow less extensive and decidedly paler. 

 Convex callosity of lateral lobes moderately but not decidedly broad. 

 Size small, form moderately slender. Male cerci similar to those of 

 nigropleuroides but not irregular in outline. Ventro-external margins 

 of caudal femora bearing normalh* one and two spines.) 



spartinae (H. Fox) 

 AA. Prosternum unarmed. Caudal tibiae armed at distal extremity with 

 one pair of spurs. (Subgenus Anarthropus) 



(Size medium to verj' small, form rather slender. \'ertex moderately ascend- 

 ing, sides decidedly divergent, greatest width nearh' one and one-half times that 

 of proximal antennal joint. E3-es normal. Convex callosity of lateral lobes 

 very broad. Abdomen with dorsum dark, bordered laterad with a narrow 

 pale line, sides infuscated. Cerci very slender, with a long, slender, median 

 (vertical) tooth situated interno-mesad, the diameter of which at its base is 

 nearly that of diameter there of shaft of cercus. Ventral margins of caudal 

 femora unarmed.) saltans (Scudder) 



It must be remembered in using the above key that single 

 characters are seldom if ever absolutely constant and that varia- 

 tion exists in all species, the characters given above, when taken 

 singly, being only correct for the great majority and not for 

 every example of the species considered. 



In every group we have carefully studied, the absolute necessity 

 of determining material not from one or two apparently striking 

 differences but from the sum total of characters, has convinced 

 us that, for correct conceptions and accurate determinations, the 

 latter method is the only safe one to follow. In conseciuence a 

 brief key for the species treated here would in our opinion only 

 lead to confusion, and in the use of the present key we feel that 



TRANS. AM. EXT. SOC, XLI. 



