392 
ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1919. 
tree trunks in late summer. Most of these cicadas probably go 
through their underground changes in one year, but there are peri- 
odical species whose lives we as yet know nothing about. 
The 17-year cicada has a thick-set body (fig. 4), the forehead is 
wide, with the eyes set out very prominently on each side. He is 
distinctively but not strikincly colored. The back is plain black 
(pi. 3); the eyes bright red; the wings shiny, transparent amber 
with strongly marked orange-red veins; the legs and beak are red- 
dish and there are bands of the snme color on the ventral rings of 
the abdomen. Each front wing is branded with a conspicuous brown 
W toward the tip. Superstition, of course, must explain this only 
as meaning " war," but the 1919 brood evidently miscalculated Avhat 
was going on above ground. 
The male cicada is noted for 
his " song," yet his music is of an 
instrumental order rather than 
vocal. He carries a pair of large 
drumheads beneath the bases of 
his wings, the ridged, parchment- 
like surfaces of which are thrown 
into rapid vibration by a pair of 
pillarlike muscles in the front 
part of the abdomen (fig. 7, 
TmMcT). Below the drums, be- 
tween the thoracic and abdomi- 
nal divisions of the bod}^ on each side, is a large cavity with tense 
membranes on its walls, which most probably act as resonators. The 
cavities are closed below by a pair of large flaps projecting back 
from the thorax, but they can be opened by the elevation of the 
abdomen. 
The female has no drums, and consequently is doomed to keep 
silence; but no one has yet discovered that she possesses ears, so it 
seems she also does not have to listen to her noisy mates. Her chief 
distinction is her ovipositor, a swordlike instrument used for insert- 
ing her eggs into the twigs of trees and bushes. Ordinarily it is kept 
in a sheath beneath the rear half of the abdomen, but when used 
(pi. 3) can be turned forward by a hinge at its base. The ovi- 
positor consists of two lateral blades and a guide rail above. The 
blades excavate the egg nests in the wood and then the eggs are 
passed into the nests through the space betAveen the blades. 
Entomologists call the 17-year cicada Tihiceiui septe'Tudecim, But 
there are two forms (fig. 4), distinguished by their size and by their 
song. The smaller form has been given the name Tibiclna cassini 
or Tibicena neptendecim cassini, according to whether it is regarded 
Fig. 
4.. — ^Males of the large and the small 
form of the cicada (natural size). 
