THE METHOD OF BUBROWING. 93 
It is difficult to say how many of these reported occurrences at 
unusual depths are due to an unobserved tumbling of specimen- from 
higher levels, but where the insects have been observed to issue through 
the bottom of cellars or similar situations the information would seem 
to be reliable. The fact remains, however, that all of the extensive 
diggings in the investigation of the early history of this insect here in 
Washington and elsewhere have confirmed the statements of Dr. Smith : 
in other words, the insects have always been found, as stated, within 2 
feet of the surface and in greatest numbers between the depths of 8 
and 18 inches. 
A curious feature in connection with the underground life of this 
insect is their apparent ability to survive without injury in soil which 
may have been flooded for a considerable period. Dr. Smith records a 
case of this kind where a gentleman in Louisiana in January. L818, 
built a milldam, thus overflowing some land. In March of the follow- 
ing year the water was drawn off and "in removing a hard bed of pipe 
clay that had been covered with water all of this time some G feet deep 
the locusts were found in a fine, healthy state, ready to make their 
appearance above ground, that being the year of their regular appear- 
ance. 1 ' Another case almost exactly similar is reported by Mr. Barlow. 
In this instance the building of a dam resulted in the submerging of 
the ground about an oak tree during several months of every summer, 
ultimatelyresulting in the death of the tree. This went on for several 
years, until the dam was washed away by a freshet, when digging 
beneath the tree led to the discovery of the Cicada larva' in apparently 
healthy condition from 12 to 18 inches below the natural surface of 
the ground. In both of these instances the ground may have been 
nearly impervious, so that the water did not reach the insects nor 
entirely kill all of the root growth in the submerged soil. 
THE METHOD OF BURROWING. 
The actions of the Cicada beneath the soil are not readily investi- 
gated, the newly hatched and more active individuals disappearing 
rather rapidly and seeming to be quite at home in the earth, as their 
natural element. The method of burrowing of the larger and partly 
grown specimens, as witnessed in captivity under fairly natural condi- 
tions, is, as has been described in the manuscript notes of the Division. 
as follows: The larva scratches away the walls of its cell with the 
femoral and tibial claws, grasping and tearing the earth and small 
stones just as one would do with the hands, bracing itself against the 
sides of its cell mainly by its hind and middle legs, the former in their 
natural position and the latter stretched out over the back. It" it is 
rising, so that the earth removed naturally falls fco the lower end of the 
burrow, it simply presses the detached portions on all sides, and espe 
cially on the end of the cavity, by means of its abdomen and middle and 
hind legs. If the direction of the larva, however, is downward, the 
