PROOFS OF LONG UNDERGROUND LIFE. Pls 
the life of the Cicada always arouses skepticism in the minds of persons 
who have not given the matter study and have not examined the 
historical records. To silence such objectors, rather than because of 
the need of experimental proof, Professor Riley was for many years 
interested in demonstrating by actual rearing experiments the period 
of underground development of this insect; in other words, to follow 
a particular generation through its subterranean life of seventeen or 
thirteen years, as the case might be, watching its development and 
preserving examples of the different stages. 
The great difficulty of conducting to a successful termination experi- 
ments of this sort will be appreciated when the long period over which 
the experiments must necessarily extend isremembered. The extreme 
delicacy and softness of the larve themselves, especially in the first 
years of their existence, introduces an additional difficulty, as the 
slightest touch or pressure injures or crushes them and renders them 
unrecognizable. It is therefore often difficult to find them, even when 
the soil is very thickly tenanted. 
The difficulty of carrying out breeding experiments with the Cicada 
under any but natural conditions is illustrated by various efforts in this 
direction undertaken by this Bureau. In one instance a number of 
newly hatched Cicada larve were allowed to penetrate the soil about a 
potted oak tree of small size. None of these larve survived for a 
single year. In another instance the larvee were allowed to penetrate 
the soil in large breeding tanks, each containing young trees, the tanks 
being planted out of doors in the soil. These were left undisturbed for 
a number of years, and although the conditions were seemingly very 
favorable for a successful outcome, when an examination was finally 
made, no traces of the larve were found. 
The earliest systematic attempts. to follow the development of the 
Cicada were made in the field in Missouri by Professor Riley, and 
subsequently continued under the latter’s direction by Mr. J. G. Bar- 
low, an agent of the Bureau. They consisted in making diggings 
from year to year under trees which were known to have been thickly 
stocked with eggs. The first records approaching in any way to 
completeness were obtained with the 13-year Brood XIX, beginning 
with its appearance in 1881. Observations on this brood were con- 
tinued by Mr. Barlow at Cadet, Mo., with a fair degree of regularity 
until July, 1891, when they unfortunately terminated. 
During the ten years over which these observations extended the 
insect had developed through all four larval stages and was ready to 
enter the first pupal stage. The first molt occurred after a period of 
from one year to eighteen months, the second molt after an addi- 
tional period of two years, the third molt after an additional period 
of three years, and the fourth molt after an additional period of 
31117—No. 71—07——8 
