22 GUIDE TO ORTHOPTERA 



ACRIDIIDAE. 



Only four of the nine subfamilies of Acridiidae are represented 

 in the United States, although three others occur in more 

 southern portions of America. Yet on the whole this family is 

 better developed in our district than is any other and contains 

 some genera, especially Melanoplus, of very great extent. 



Subfamilies of Acridiidae. 



A. 1 . Claws without arolium; pronotum extending over the 



abdomen ; tegmin a lobiform. . . . . Tettiginae. 



A. 2 . Claws furnished with an arolium ; pronotum extending at 



most over the extreme base of the abdomen ; tegmina generally 



well developed, but sometimes abbreviate, lobiform or wanting. 



ft 1 . Prosternum without marked prominence (sometimes with 



an obtuse tubercle); arolium usually small or rather small. 



c l . Face retreating and angulate at meeting with vertex ; 



foveolae generally well developed; fastigium usually but 



little declivent ; eyes generally longer than the intraocular 



portion of the genae ; mediastinal and scapular fields of 



tegmina generally regularly reticulate by transverse veins. 



Tryxalinae* 



c 2 . Face nearly or quite vertical, and rounded at meeting 

 with vertex ; foveolae generally obscure ; fastigium usually 

 strongly declivent; eyes generally shorter than the infra- 

 ocular portion of the genae ; mediastinal and scapular fields 

 of tegmina generally very irregularly reticulate. 



Oedipodmae* 



b*. Prosternum armed anteriorly with a distinct conical or 

 cylindrical spine. . . . . . . Acridiinae. 



* These two subfamilies are occasionally difficult to distinguish, and I accordingly 

 give here, in an English form, the detailed distinctions laid down by Stal (Rec. 

 Orthopt., i, 6-7). 



Fastigium of vertex not or slightly, rarely strongly, declivent ; front trending more 

 or less, generally strongly and obliquely, backward ; eyes generally longer than the 

 inf raocular portion of the genae, rarely shorter or of equal length, and in these cases 

 the front is very oblique; antennae sometimes ensiform, inserted between the middle 

 or below the middle (inter medium vel pone medium) of the eyes. Metazona rarely 

 longer, generally shorter than the prozona, the hind margin rarely rectangulate or 



