21 2 ORTHOPTERA. 



Interocular space much wider than the frontal costa, the 



latter not sulcate. 

 Vertex very short and greatly depressed. Pronotum 



glabrous. 



Tegmina wanting Rhicnoderma, Gerstaecker. 



Tegmina present, but rudimentary Dio/EARchus, Stal. 



Vertex produced into a heavy spike that exceeds the 



pronotum in length ; the latter tuberculate. Tegmina 



and wings present Bactrophora, Westwood. 



Pronotum with the metazona triangulately produced, a's 



long as, or longer than, the prozona Trybliophorus, Serville. 



Frontal costa continued to the labrum. Tegmina 



lobiform. Second joint of hind tarsi not elongate. 



Posterior femora with smooth carinse Jivarus, Giglio-Tos. 



Mesosternal lobes contiguous,, at least in the male . . . Prorachthes, Gerstaecker. 

 Posterior tibiae provided above with an apical spine inter- 

 nally only, the external one wanting (except in Abila 



and Aristia). 

 Posterior tibiae expanded apically, the margin acute. 

 Mesosternal lobes touching in a straight suture for 



the greater portion of their length. The tegmina 



acuminate. 

 Fastigium of the vertex as long as, or longer than, the 



longest diameter of the eyes. 

 Fastigium of the vertex broadly grooved longitudinally 



in the middle Leptysma, Stal. 



Fastigium of the vertex without a longitudinal groove . Cylindrotettix, Bruner. 

 Fastigium of the vertex shorter than the eyes .... Arnilia, Stal. 

 Mesosternal lobes more or less distant. Tegmina sub- 



acuminate or rounded at their tip. 

 Posterior margin of the pronotum rounded. Tubercle 



of the prosternum conical, more or less acute. 

 Body very graceful or slender. Front strongly oblique. 



Head much exserted, conical. Antennse distinctly 



ensiform. Eyes rather elongate, viewed from above 



strongly convergent, meeting at an acute angle. 



Pronotum distinctly dilated posteriorly, the lower edge 



of sides straight, oblique. Tegmina somewhat dilated 



toward the apex Inusia, Giglio-Tos. 



68 (67). Body heavier. The front less oblique. Head gently 



exserted, not conical. Antennse filiform or subensiform. 



Eyes not at all, or but little, elongated, when viewed 



from above slightly convergent, forming an obtuse 



50 



(49). 



51 



(54). 



52 



(53). 



53 



(52). 



54 



(51) 



55 



(40) 



56 



(39). 



57 



(38). 



58 



(!)■ 



59 



(74). 



60 



(65). 



61 



(64) 



62 



(63) 



63 



(62) 



64 



(61) 



65 



(60) 



66 



(71) 



67 



(68) 



