54 
THE PERIODICAL CICADA. 
the soil, the taking of food is a constant feature. The structure of the 
mouth parts in these preliminary stages is identical in essentials with 
that of the adult, and the characteristic features are illustrated in the 
foregoing figures with subjoined explanations. 
In the taking of food by the larva? and pupae, as they 
rest on the rootlets in their earthen cells, the tip of tbe 
beak, namely, the lower lip, is brought to bear on the 
root, and by alternating longitudinal thrusts of the seta?, 
especially the upper pair, which are the stronger and 
which represent the great jaws or mandibles of biting 
insects, the soft, succulent layers of the cambium beneath 
the bark are reached, the slender setae being supported, 
strengthened, and directed by the stronger and encir- 
cling sheath-like lower lip. The irritation caused by this 
puncture induces a flow of sap, which passes up between 
the seta? to the lower lip and within this along the basal 
portion of the seta? into the mouth or throat by suction, as 
in higher animals. 
THE OVIPOSITOR. 
Fig. 23.— The peri- 
odical Cicada, side 
view of female to 
show beak, a, and 
ovipositor, b 
(after Riley). 
Fig. 24. — Abdomen of female showing ovipositor 
and attachments: a, ventral, b, lateral, and c, 
dorsal view (original). 
The ovipositor, or twig-pierc- 
ing and egg-laying organ, of the 
female Cicada is also a very com- 
plex instru- 
ment. It is- 
sues from a 
groove, or 
fissure, on 
the under- 
side of the abdomen, and at rest is nearly concealed 
except at the tip by the broad overlapping sides 
of the eighth dorsal segment. The ovipositor 
proper is protected and covered when at rest by 
two valves, which form a sort of sheath, or scab- 
bard. The inclosed ovipositor is a very tough, 
horny instrument, spear-shaped, aud seriated 
at the extremity, and consists of three pieces, 
namely, a back portion (probably two pieces 
grown together), which acts as a supporting or 
connecting piece for the two lateral blades. These 
lateral pieces, or blades, slide up and down in 
alternation on tongues projecting from the central 
or supporting piece, have serrated cutting edges, 
and are the chief agents in piercing twigs prepar- 
atory to the deposition of eggs (fig. 25). The relative position of the 
three parts of the ovipositor and the nature of the locking tongues, 
Fig. 25.— Tip of ovipositor, 
much enlarged: a, from 
above, 6, from beneath, 
with dotted portion to 
show the alternating mo- 
tion of the side pieces 
(original). 
