52* 
THE PERIODICAL CICADA. 
three-jointed beak is to be noted ; the legs not especially large or strong 
except for the anterior femora, which are much thickened; in the 
female the complex instrument for the deposition of eggs projecting 
from a fissure or slit in the lower surface of the abdomen, and the 
blunter abdomen of the male without the fissure beneath, but with two 
large ventral plates at the base of the abdomen covering the sounding 
disks of the vocal apparatus. The latter is located on either side of 
the base of the abdomen and appears as two inflated ribbed drums of 
lighter color than the general body surface. 
The structure and workings of the more important organs, namely, 
the beak, the ovipositor, and the vocal apparatus, follow in some detail. 
• THE MOUTH PARTS, OR BEAK. 
In the order of insects to which the periodical Cicada belongs, though 
vastly modified, it is possible to trace all the essential parts found in 
Fig. 21 .—Head of Cicada, front view, showing the normal position of mouthparts on the left, and 
with the raandihle and maxilla drawn out on the right— for description, see tig. 22 (author's 
illustration). 
the mouth of true biting insects, namely, the upper lip (labrum), the 
main pair of jaws (mandibles), the second or lower pair of jaws (max- 
illae), and, beneath, the lower lip (labium). Within also are the two 
tongues, one projecting from the roof of the mouth (epipharynx), and 
the other (hypopharynx) attaching to the upper base of the lower lip. 
These tongues are short, and of service probably in facilitating the 
suction necessary in raising the fluids of the plant to the mouth. They 
do not extend beyond the mouth cavity and never enter the plant tissues. 
