92 THE PERIODICAL CICADA. 
THE LOCATION IN THE SOIL. 
There has been a great deal of difference of opinion as to the depth 
beneath the soil reached by the larvae and pupa?. In all of the exten- 
sive excavations which have been made on the Department grounds in 
following the results of the experimental plantings specimens have 
rarely been found at a greater depth than 2 feet below the surface and 
usually between G and 12 inches, especially in the first years of the life 
of the insect. This experience is corroborated by the examinations 
made by Professor Riley in Missouri, and is fully confirmed by the inter- 
esting manuscript notes left on this subject by Dr. Smith, which are 
here reproduced: 
The depth in the earth to which it descends depends npon that of the vegetable 
soil, and its location is at the bottom of the soil, except perhaps in some of the deep 
soils of the West and the alluvial soils, where the depth of its descent is probably- 
only sufficient to protect it against the inclemency of the weather. This is generally 
from 12 to 18 inches and sometimes 2 feet. It never changes its locality from the 
time it enters the earth till it emerges. The cells in which they shut themselves up 
are, inside, well finished and smooth, of a sufficient size to accommodate them; but 
outside they are mere lumps of clay, and afford by their appearance no clew to their 
internal character. It is this fact that has caused all the doubt and mystery about 
their place of residence and habits duriug their long continuance in the earth. A 
gentleman in the winter of 1850-51 was excavating on the side of a low hill for the 
purpose of building a wall on West Baltimore street. The excavation was about 150 
yards long and 6 to 18 feet deep to the level of the paved street. This hill had been 
covered in former years with trees and shrubbery, and had been one of the fields of 
observation in 1834. I watched this excavation daily and found the cells of the 
locusts thrown down in the greatest abundance. The lumps of earth containing 
the cells would roll down the heaps of earth just as others did, affording not the 
slightest indication of their internal contents. But as the pick or the spade of the 
workmen struck a cell in its place in the banks it readily broke open and the larva 
was exposed. When the excavation was completed the observer standing in the 
street had a fine view of the broken cells in the bank. From one end of the bank 
to the other the cells were plainly visible, appearing like small augur holes, and all in 
a regular stratum of earth about 18 inches below the surface of the earth, from 2 to 4 
or 5 inches apart, and none more than 1 or 2 inches higher or lower than the others. 
The internal size of the cells was from l-£ to 2 inches long and about three-fourths of 
an inch wide, forming an oblong cavity very smooth in its walls. The particles of 
earth of which the cells were composed had evidently been agglutinated together 
by some viscid fluid secreted by the insect. This is their habitation during the whole 
seventeen years, or until they prepare for their ascent. 
In the face of the testimony given above there are records also by 
apparently trustworthy observers which seem to indicate that the larvae 
are capable of going to much greater depths. An instance of this sort 
is reported by Mr. Sadorus, of Port Byron, 111., who built a house in 
1853 and found that they came up in his cellar in 1854. Others have 
reported finding them at a depth of 10 feet or even more below the sur- 
face. A rather remarkable instance is recorded by Mr. Henry C. 
Suavely, of Lebanon, Pa., in which the Cicada pupae are reported to 
have worked their way through a hard mass of cinders about 5 feet in 
thickness, which had been firmly compacted. 
