1915] 



Nininger — The Mouthparts of Orthoptera 



15 



Fig. 1. Mouthparts of Locust, Genus Hippiscus. (Hypopharynx omitted.) 

 1, labrum; 2. mandibles; 3, ma.Killse; 4, labium. 



Some of the constant characteristics of the mandible of locusts 

 may be stated as follows: 



1. The left mandible is generally slightly, and sometimes con- 

 siderably larger than the right one; and projects beyond it ventrally 

 when closed. 



2. The distal ends of the two mandibles are always beveled, the 

 one in the opposite manner from the other so that when the man- 

 dibles are closed these beveled surfaces are contiguous throughout. 



3. When the mandibles are closed the anterior aspect presents 

 the cutting edges meeting, not on the median line, but always to 

 the right of it. (Plate 1, fig. 4a). 



