HEAD, MOUTH-PARTS, ORTHOPTERA EUPLEXOPTERA 279 



the ventral. The caudal portion of the subgusta is flattened, 

 the cephalic portion is convex, and there is a constriction near 

 the middle. Laterocephalad of each lingula is a less chitinized 

 triangular area similar to the one in Blatta. The tendency to 

 asymmetry occurs in the ental arms of the lingula, in the ellip- 

 tical area cephalad of them, and in the patches of brownish 

 spinulae. Those on the dextral side are more advanced in posi- 

 tion and more conspicuous than the sinistral. The salivia is a 

 large, distinct, triangular sclerite cephaloventrad of each lingula 

 and ventrad of the triangular area mentioned above. The apex 

 of the triangular salivia is produced ventromesad into a long 

 pointed extension which, on reaching the meson, supports the 

 salivos. The ventral surface of the hypopharynx is mem- 

 branous and broadly and deeply folded. The middle portion of 

 the membrane is folded over itseK and forms a deep pocket into 

 which the distal portion is retracted. This retractile portion is 

 covered with pseudotrachea-like thickenings which extend from 

 the main mesal trunk to the sides in an oblique parallel manner. 

 These smaller thickenings unite on the lateral margin into a 

 large lateral trunk which converges cephalad and extends over 

 the distal margin onto the dorsal surface of the hypopharynx. 

 This pseudotracheated portion may be evaginated and protruded 

 much further cephalad than the distal margin of the labium. 

 Figure 157 represents this portion slightly out of place. The 

 oscula is narrow cephalad of the salivos, deeply folded around 

 the ventral margin of the salivia, and is produced on each lateral 

 aspect where it merges into the labicoria. 



In Orchelimum (fig. 158) the parapharynx is well developed 

 and linguiform. The pharyngea is long, slender, slightly chit- 

 inized, and extends along each side of the subgusta and then 

 obliquely dorsad into the lateral wall of the postpharynx. The 

 paralingua is the ax-shaped sclerite fused to the cephalic end of 

 each pharyngea. Its ventrocaudal arm is directed mesad and 

 then laterad and is connected with the mandible by a poorly 

 differentiated linguacuta. The lingula is distinct and fused to 

 the dorsocephalic angle of each paralingua; a mesal extension 

 from its dorsal margin constricts the parapharynx at this point. 



