94 THE PERIODICAL CICADA. 
is a reproduction of a photograph of a small area of a cone-covered 
district. 
Two very elaborate accounts of these structures, by Mr. Benjamin 
Lander and Dr. E. G. Love, were published in 1894-95, the authors 
seeming very near the actual truth in their explanation of the 
phenomenon. Mr. Lander describes the occurrence of the cones as 
noted by him as follows: 
On the 4th of May, 1894, while in the woods on the summit of South Mountain, at 
Nyack, N. Y., I came upon a spot that had recently been burnt over. On this area I 
observed vast quantities of the Cicada structures, entirely closed, averaging about 24 
inches in height, the aggregation ending at the very edge of the burnt section. So 
thickly studded was the ground thay often eight or ten would be found in the space 
of a square foot; in one case I counted twenty-three in such a space. Subsequent 
explorations showed that the Cicada city extended over an area of not less than 60 
acres. Eight large aggregations were discovered by me on top of the Nyack hills and 
the Palisades, covering many acres, and one near a stone quarry at a lower elevation— 
none of them in a place subject to overflow. Later, when only the ruins of the domes 
remained, I visited two areas where large numbers had been found, one in ground 
thinly covering massive sandstone and another hard by a quarry, where the top soil 
was thin. 
The explanation offered by Mr. Lander is that the dome builders, 
owing to the shallowness of the soil, determined either by the nearness 
of the underlying rocks’ or of a subsoil of a character preventing the 
insects working in it effectively, had responded more quickly to the 
heat of spring and early summer, and the pupe coming prematurely 
to the surface closed and extended their burrows as a means of pro- 
tection while awaiting maturity. The extension of the gallery ehove 
the ground, though not suggested by Mr. Lander, may be explained 
by the same instinct which impels the insect to burrow upward from 
its subterranean cell, 
In substantiation of his theory, Mr. Lander calls attention to the 
weather records for March and April, 1894, which indicate an unusually 
high temperature throughout the region of the domed burrows, 
causing wild plants to bloom a month before their ordinary season. 
The occurrence of these structures over burned areas, which would be 
acted upon more quickly by the sun, supports his belief. Additional 
support of the same kind is an instance recorded by Prof. J. B. 
Smith in a letter received from Mr. J. H. Willets, of Port Elizabeth, 
N. J. The latter states that ‘On April 24 a fire from the South 
Jersey Railroad burned over several hundred acres of woodland, 
leaving the earth bare. Six days afterwards these fresh holes and 
raised tubes appeared, and yesterday the whole surface was literally 
covered with them.”’ In further description he says: 
Imagine yourself standing out in the woods in south Jersey on 100 acres of recently 
burned ground with millions and millions of raised tubes of new earth (clay ground) 
aAnnual Report State Entomologist of New Jersey for 1894, 
