HEAD, MOUTH-PARTS, ORTHOPTERA EUPLEXOPTERA 271 



row transverse sclerite (ch) caudad of the submentum. This 

 piece, which is separated from the submentum by a dist net 

 suture, has been designated as the 'submentum' by Packard 

 ('83) and by practically all other writers, who have considered 

 the large sclerite cephalad of it as the mentum and which is 

 here designated as the submentum. This so-called 'submentum' 

 is one of the sclerites of the microthorax. It is interesting to 

 note that Hansen ('94) found a similar piece in Hemimevus, 

 and the labium, according to his figures, is very similar to that 

 of Anisolabis. In Diapheromera the caudal two-thirds of the 

 submentum is membranous except for a narrow area along each 

 lateral margin and a variable ovate area on the meson. The 

 suture between submentum and mentum is distinct and com- 

 plete, except in Melanoplus where the mesal portion is cbsolete. 

 The lateral lobes are distinct, except in Melanoplus and Tettix; 

 they are best developed in Anisolabis. 



The mentum is narrow, transverse, and distinctly smaller 

 than the submentum in Diapheromera, Gryllus, Stenopelmatus, 

 and Anisolabis; is more or less distinct in Melanoplus and 

 Tettix; and is indistinct in Mantis and Orchelimum, where it 

 is fused with the stipulae without indication of sutures. The 

 caudal margin of the mentum in Orchelimum, Stenopelmatus, 

 Melanoplus, and Tettix slightly overlaps the cephalic margin of 

 the submentum and is at a higher level than the latter. 



The stipulae are subquadrate and distinct in all except those 

 where the naentum has fused with the stipulae. They are 

 elongated in all except Gryllus and Melanoplus, where they are 

 transverse. The mesarima is very deep in Mantis; moderately 

 deep in Orchelimum and jNIelanoplus, and reaches the cephalic 

 margin of the mentum in Anisolabis. The fundarima extends 

 caudad as a chitinized thickening in Diapheromera, Gryllus, 

 Orchelimum, Stenopelmatus, and Tettix. In the last four 

 genera, the caudal end is connected with thickenings which 

 extend laterad. The suture which separates each stipula from 

 a glossa and paraglossa is complete in Gryllus, Melanoplus, Tet- 

 tix, Anisolabis, and incomplete in the others. It is entirely 

 wanting on the dorsal surface. 



