8 THE PERIODICAL CICADA. 
According to the records they appeared in 1868 earlier in the South 
than in the North; but the last half of May can be set down as the 
period during which they emerge from the ground in any part of the 
country, while they generally leave by the 4th of July. In Saint Louis 
County, Mo., in 1868, they commenced issuing on the 22d of May, and 
by the 28th of the same month the woods resounded with the rattling 
concourse of the perfect insect. As is the case with a great many other 
insects, the males make their appearance several days before the females, 
and algo disappear sooner. Hence, in the latter part of the Cicada 
season, though the woods are still full of females, the song of but very 
few males will be heard. 
That circumstances favorable or otherwise may accelerate or retard 
their development was accidentally proven, in 1868, by Dr. E. 8. Hull, of 
Alton, Illinois, as by constructing underground flues for the purpose of 
forcing vegetables, he also caused the Cicadas to issue as early as the 
20th of March, and at consecutive periods afterwards till May, though, 
strange to say, these premature individuals did not sing. They fre- 
quently appear in small numbers, and more rarely in large numbers, 
the year defore or the year after their proper period. This is more es- 
pecially the case with the 13-year brood. Thus, in Madison County, in 
Illinois, and in Daviess and Clark Counties, in Missouri, there were 
in 1854 a few precursors of the true 1855 brood. They were also ob- 
Fic. 2.—Seventeen-year Cicada: a, pupa; b, cast pupa shell; ¢c, ima- 
go; d, punctured twig; e, twoeggs. (After Riley.) 
served in Madison County, Ilinois, in 1867, while “‘L. W.”, writing from 
Guntersville, Ala., to the Country Gentleman, of June 25, 1868, says, 
‘some call them 14-year locusts.” Other such cases will be noticed 
hereafter. 
