98 CRABS AND INSECTS. 
known as /adial palpi. Near the compound eyes rise the 
sense-organs, or antenna. The ¢horax is separated into 
three segments : the first, prothorax, bearing the first pair 
of legs ; the second segment, or mesothorax, bears the elytra 
or first pair of wings—in the beetles, hard, chitinous store- 
house for the wings proper (here is also attached the sec- 
Hetathoraz, 
Labium, ---------- # 
Mavilla. 4 ? 
SUES SP Secs! Mouth-parts, 
6 sj 
3 
Elytron, or first 4 
wing, = eeeneenn ene ‘Meeothoraz. x 
as 5 
ABDOMEN. 
Fic, 110.—Skeleton of common beetle. (After Morse.) 
ond pair of legs) ; the third segment, or metathorax, bears 
the third pair of legs and the second pair of wings, that 
are elastic membranes stretched over a framework of 
tubes. The abdomen bears the sting, ovipositor, or spin- 
nerets, as the case may be. The legs are generally com- 
posed of from six to nine joints, and usually terminate in 
two hooks, with perhaps pads or suckers (Fig. 111). 
Digestion —The mouth-parts (Fig. 112, @) are modified 
in different insects for sucking, biting, stinging, etc. The 
