192 FAMILY VI. - ACRIDIDJE.- THE LOCUSTS. 



never brightly colored or with a black band. 



I. TRYXALINE, p. 192. 



6&. Face nearly or quite vertical and rounded at its junction with 

 the vertex; foveolse present and visible from above; median 

 carina of pronotum often more or less crested and usually cut 

 by more than one sulcus; wings usually bright colored and 

 generally with a black band. II. OEDIPODIX.E, p. 243. 



oo. Prosternum armed between the front legs with a distinct conical or 

 cylindrical tubercle; face vertical or nearly so; pronotum with dor- 

 sal surface flattened, never strongly crested, tuberculate or rugose; 

 wings, when present, transparent, never with contrasting colors. 



III. LOCUSTIX.E, p. 302. 

 Subfamily I. TRYXALINJE. 



THE SLANT-FACED LOCUSTS. 



The members of this subfamily have the vertex horizontal or 

 a little ascending ; face usually decidedly'oblique and meeting the 

 vertex at an acute angle; lateral foveola? sometimes present and 

 well developed, in most of our eastern genera absent or invisible 

 from above; eyes usually longer than that portion of the cheeks 

 below their orbits; antenna? variable, sometimes depressed toward 

 base and acuminate, usually inserted between the middle or be- 

 low the middle of eyes; pronotum with surface of dorsal field 

 generally smooth, prozona not shorter than metazona, front and 

 hind margins of nearly equal width, lateral carinse usually dis- 

 tinct; tegmina and wings often short and imperfectly developed, 

 long and short winged forms of the same species being not un- 

 common ; tegmina with intercalary vein generally wanting, costal 

 area often expanded and regularly reticulate by transverse veins. 



Certain forms of Tryxalime are very difficult to distinguish 

 from some of the Oedipodina?, and their reference to either group, 

 as Brunner (1893, 103) has said, "est nn pen arbitraire et repose 

 sur restimation personelle" ; i. e., somewhat arbitrary and a mat- 

 ter of individual opinion. In general it may be said that the Try- 

 xalina 1 have more slender bodies than the Oedipodime, and often 

 somewhat elongate, cone-shaped heads, recalling the Copiphorina? 

 of the Tettigoniid?p. The coloration is also more variable, there 

 being often distinctly green and brown forms with all the inter- 

 mediate tints in the same species. In our eastern species of Oedi- 

 podina? this variation occurs only in the genus ChortopJiaf/a. 

 This variation of coloration is used as a means of protection, often 

 rendering the insect almost invisible when feeding. The hind legs 

 are more slender-than those of most of the Oedipodina? and the 



