72 THE PERIODICAL CICADA. 
ing from their weight. This point seems to have been the eastern 
border of the swarm, and a few rods farther up the Cicadas became 
very scattered and soon ceased altogether. 
They often also appear in greatest number in rather well-defined 
districts within the general range of the brood, or, in other words, are 
irregular in local distribution. This variation in abundance is due in 
some cases to differences in the character of the soil, and in others per- 
haps to varying surface conditions, as of timber growth, etc. They 
prefer, apparently, white oak groves, and are most abundant where 
the land is high and well drained and the soil a rich sandy loam with 
a sandy or soft clay subsoil. The irregularity of local distribution is 
confirmed also by the experience of Mr. Davis on Staten Island, who 
reports of the 1894 brood that they were very rare in sandy districts, 
while in districts less sandy they appeared by thousands. He says 
also that they occurred by millions on certain hills and in certain bits 
of woodland, yet at a short distance away, under apparently unaltered 
conditions, they were very scantily represented. 
The local abundance of the Cicada in well-defined districts is also to 
be explained by the fact, already noted, that the winged insect is slug- 
gish and scatters but little from the point of emergence, which, with 
favoring circumstances, tends constantly to concentrate rather than to 
scatter the species. 
THE FOOD HABITS OF THE ADULT INSECT. 
The taking of food in the adult stage seems to be of rare occurrence, 
and has been observed and commented upon by few of the entomolo- 
gists who have studied the species. That the periodical Cicada feeds 
at all has even been questioned, and it is quite possible that in some of 
the cases where it was supposed to have been feeding the action of the 
insect was misinterpreted. Such feeding is limited, at any rate, to the 
. female, as in this sex only do we find a perfect digestive apparatus, 
that of the male being rudimentary. One of the most reliable accounts 
of the feeding of the adult Cicada is given by Mr. Davis, who reports 
that the black birch and the sweet gum are its favorite food plants, and 
that it is not uncommon to see rows of Cicadas along the branches of 
these trees with their beaks embedded in the bark. 
Whether in this case all of the insects were actually feeding or not 
is doubtful, and at any rate no appreciable injury from the feeding of 
the adult insect has ever been noted, even on trees where they occurred 
in countless myriads. 
THE CICADA AS AN ARTICLE OF FOOD. 
The fact has already been alluded to that the common name "locust," 
given by the early colonists to this insect, was undoubtedly owing to 
a confusion of the Cicada with the migratory locust of the Orient, 
which has been an article of diet from the earliest times, and is so 
