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which are built by the pupa of the periodical cicada above ground 
shortly before the adults issue. Dr. Lintner brought together the facts 
concerning a large number of observations made the present year, and 
showed that the earlier supposition of Eiley and others, that these 
chimneys are built only in wet ground, is unjustified, and showed fur- 
ther that the orifice at the bottom of the chimneys and next to the sur- 
face of the ground, as figured by Riley, is at least abnormal. Dr. Lint- 
ner was, however, unable to give a satisfactory explanation of the cause 
of this chimney-building. 
Mr. Benjamin Lander, in the Scientific American for October 13, pub- 
lishes a lengthy communication on the same subject, accompanying it 
with very good illustrations of the chimneys, both entire and in section, 
and offering an explanation which is new. His observations lead him 
to believe that these chimneys are built only where the soil is very thin 
and covers a rock ledge. He showed further that the month of April 
was phenomenally hot, and he concludes that the pupae in the shallow 
earth, covering the smooth, unbroken, impervious rock, would be early 
stirred to activity by the unwonted heat, and would build their burrows 
to the surface in advance of those in deeper and cooler ground, obeying 
the same impulse that the latter would feel when the warmth of the 
more advanced season should reach their more remote abiding places. 
Especially would this be the case where the woods had been recently 
burned over, as was the case with several chimney localities which Mr. 
Lander observed. The closed extensions to the short burrows Mr. Lan- 
der therefore supposes to be built as a protection from premature heat 
and possibly to shut out injurious intruders during the accidentally 
lengthened period which they would have to wait for full development. 
This strikes us as an ingenious theory, and likely to be to a certain 
extent correct, provided no exceptions to the rule of shallow soil be 
found. Our own experience with these chimneys is, however, too 
limited to justify criticism. A well-known entomologist recently sug- 
gested to us in conversation the idea that inasmuch as the chimneys 
are most frequently built upon ground which is comparatively free 
from trees and shrubs, they are constructed to provide the pupa with 
an eminence upon which to crawl and to which to attach itself while 
shedding its skin and unfolding its wings. That it seems necessary 
for the insect to crawl upon a tree, a shrub, a fence, or something of 
that sort to perform this operation is well known, and this theory, too, 
is therefore very plausible, provided it be found that the chimneys are 
confined to comparatively open places. If we remember correctly, 
however, one of Dr. Lintner's photographs showed the chimneys to be 
very abundant in a patch of comparatively dense undergrowth, and we 
have also seen them in a grove of large trees. 
8359— No 3 5 
