194 



FAMILY VI. ACRIDILLE. THE LOCUSTS. 



c. Disk or scutellum of vertex with a distinct longitudinal median 



carina; antennae usually more or less flattened but not 



strongly tapering. Tribe II. AMBLYTROPIDI, p. 207. 



cc. Disk of vertex without a median carina; antennae filiform, 



rarely flattened, usually not longer than head and thorax 



together. Tribe III. ORPHULI, p. 222. 



bb. Foveolae of vertex always present, visible from above (Fig. 84, 



c.) ;face usually nearly vertical. 



d. Median carina of pronotum not high and sharp and not cut in 



or in front of middle; intercalary vein of tegmina not very 

 strong; vertex without a median carina, its lateral foveolas 

 large, distinct. Tribe IV. CHORTHIPPI, p. 233. 



del. Median carina of pronotum high and sharp, cut in or in front 

 of middle by the principal sulcus (Fig. S3, e, f, ) ; intercal- 

 ary vein of tegmina very strong; vertex with a more or less 

 distinct median carina, its foveolae small, triangular and 

 basal. Tribe V. MECOSTETHI, p. 238. 



Tribe I. TRYXALINI. 



Slender bodied grasshoppers having the sexes 

 very unequal in size, the males much the smaller; 

 head conical, horizontal or ascending, vertex dis- 

 tinctly produced in front of eyes, its apex more or 

 less augulate; foveolae wanting or indistinct; face 

 strongly declivent; antennae strongly triquetrous or 

 ensiform, usually equal to head and pronotum in 

 length, female, or longer, male; pronotum with me- 

 dian carina distinct, front margin truncate, lateral 

 lobes vertical. The tribe, as thus defined, is repre- 

 sented in our territory by four genera. 



KEY TO EASTERN GENERA OF TRIBE TRYXALINI. 



a. Head distinctly longer than pronotum, strongly as- 

 cending; knees of hind femora with their apical 

 angles strongly produced; spines of outer margin 

 of hind tibiae minute, about 25 in number; tegmina 

 much shorter than abdomen. (Fig. 72.) 



I. RADINOTATUM. 



Head sometimes equalling, never exceeding the pronotum in length, 

 feebly ascending or subhorizontal ; knees of hind femora with apical 

 angles not produced but roundly deflexed; spines of outer margin 

 of hind tibiae stouter, not over 20 in number. 



b. Prosternum without a tubercle between the front coxae; front half 

 of lower margin of lateral lobes of pronotum strongly oblique; 

 sides of fastigium strongly curved, its apex distinctly rounded. 



II. TRYXALIS. 



Fig. 72. Head 

 and pronotum 

 of Radinota- 

 tnm showing 

 ensiform an- 

 tennae, short 

 wings, etc. 



(After R.&H.) 



aa. 



