68 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I37 



Acridoid mandibles have been classified in three main types (Isley, 

 1944/ Williams, 1954), which are correlated with the type of food 

 plants preferred by the insects. The mandibles of the grass-eating or 

 graminivorous grasshoppers have the incisor lobes provided with 

 blunt teeth, and the molar areas formed by a series of ridges and fur- 

 rows. In this type, the left mandible only slightly overlaps the right 

 one. 



aa ^-xap 



i^\ 



ma' 



li- 



ma 



^ _IilI __} 



Fig. 3. — Mandibles of Marellia reniipcs. 



A, right mandible, anterolateral view. B, left mandible, anterolateral view. 

 C, right mandible, mesal view. D, left mandible, mesal view. 



aa, anterior articulation of mandible ; ap, adductor apodeme of mandible ; 

 il, incisor lobe ; ma, molar area. 



The mandibles of grasshoppers that feed on broad-leaved plants — 

 which have been called the herbivorous or forbivorous type — present 

 an incisor lobe armed with pointed, sharp-edged teeth, and their molar 

 areas consist of several pointed teeth around a central cavity. In the 

 herbivorous type of mandibles, the left considerably overlaps the right 

 one. 



The third or intermediary type occurs in the grasshoppers that feed 

 on either type of plants, and their characteristics are intermediate. 



1 Isely, F. B., Correlation between mandibular morphology and food speci- 

 ficity in grasshoppers, Arm. Ent. Soc. Amer., vol. 37, pp. 47-67, 4 figs. 1944. 

 The present writer has not seen this work and cites it through references made 

 by Uvarov (1948) and Williams (i954)- 



