284 Annals Entomological Society of America [Vol. XII, 



process arises. The inferior apophyses join the ends of the 

 bar, while the arms of the bifurcate process are connected with 

 the rami of the inner valves. These connections are thus quite 

 similar to those of the Tettigoniidas (cf. Ceuthophihis). 



The inner valvulae are very short, but not vestigial as in 

 the Gryllidse. They are connected almost to their apices by 

 the intervalvular membrane, the rami being united distally 

 by a V-shaped pons valvularum. 



Extending cephalad from the basal articulation of the dorsal 

 and ventral valvulae into the body-cavity as far as the seventh 

 segment is a somewhat flattened and heavily chitinized rod 

 (pap), which is entirely concealed in an external view. This 

 structure appears as though grooved externally, but the groove 

 is covered over with thin chitin, so that it is really a tubular 

 invagination. It serves for the origin of the most powerful 

 muscles of the valvulae, i. e., the elevators of the dorsal and 

 depressors of the ventral valvulae. Its morphological nature 

 has been the subject of differences of opinion. Lacaze-Duthiers 

 Hoc. cit.) interpreted it as the "epimerite" (valvifer), while 

 Graber {loc. cit.) thought it represented the superior apophysis 

 of the dorsal valvulae. The latter interpretation is obviously 

 incorrect; the former is much nearer the truth. The muscles, 

 which in other Orthoptera arise from the ninth tergal apodeme 

 and its vicinity and are inserted into the superior apophyses, 

 take their origin in the Acrididae from this rod, the apodeme 

 being undeveloped in its usual situation. It will be remembered 

 that this apodeme is continuous with that of the lower edge of 

 the valvifer in the Tettigoniidae and other groups, and that it 

 tends to be best developed towards its lower end, where it is 

 sometimes raised into a distinct process (e. g. Diapheromera, 

 Stagmomantis) . As the muscles which usually connect the 

 valvifer with the superior intervalvula arise in Melafioplus 

 also from this process, it appears that the latter represents in 

 part the lower end of the tergal apodeme and in part the 

 valvifer. That it does not represent the main body of the latter 

 is clearly shown by an examination of both nymph and adult 

 of one of the small grouse-locusts (Acrydiidae, more commonly 

 known as Tettiginae). Fig. 28 represents the end-segments 

 of the female nymph of Acrydiiim ornatum Say. Here we find 

 a perfectly typical valvifer of considerable size. In Fig. 26, 

 which is taken from an adult Acrydium, the valvifer is also 



