COLEOPTERA. 



503 



were supposed, for a time, to be represented by the elytra or wing- 

 covers. See pages 494 and 495, where this unfortunate error is dis- 

 cussed. 



Each sternum or ventral part of each thoracic segment is composed 



Fig. 611. — Ventral aspect of a beetle, Enchroma gigantea: /, 

 head; 2 C , gena of the epicranium: 3, eye; 7, antenna; //, 

 thorax; 14, prothorax; i4 e , proepisternum or episternum of 

 the prothorax; 14', proepimeron or epimeron of the prothorax; 

 14'. prosternum; 15, mesothorax; 15 s , mesoepisternum; 15', 

 mesoepimeron; 15 1 , mesosternum; 16. metathorax; i6 e , meta- 

 episternum; i6 f . metaepimeron; 16', metasternum; i6 u , ante- 

 coxal piece of the metasternum; 17", coxa; 17* 1 , trochantin; 

 :7 b , trochanter; 17°. femur; i7 d , tibia; i7 e , tarsus; i7 el , tarsal 

 claws; i7 e2 , pulvilli; 18, elytron. 



of a single sclerite (Fig. 608. /.) As indicated above, the three sterna 

 are designed as the prosternum, mesosternum, and metasternum, 

 respectively. 



In some beetles the metasternum is divided into two unequal por- 



