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, Enchronta gigantea: /, 
head; 2 C , gena of the epicranium; 3, eye; 7, antenna; //, 
thorax; 14, prothorax; 14®, proepisternum or episternum of 
the prothorax; i4 r , procpimeron or cpimeron of the prothorax; 
14 1 , prosternum; 15. mesothorax; 15", mesoepisternum; 15', 
mesoepimeron: 15 1 , mesosternum; 16, metathorax; x6«, meta- 
episternum; if/, raetaepimeron; 16*, metasternum; i6 u , ante- 
coxal piece of the metnsternum; 17®, coxa; 17®*, trochantin; 
i 7 b , trochanter; 17®. femur; i7 d , tibia; 17®, tarsus; 17®*, tarsal 
claws; t 7®3, pul villi; t8, elytron. 
of a single sclerite (Fig. 608. z.) 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- 
