THE DOG-DAY HARVEST-FLY. 
217 
periods so distant that vegetation often has time to recover 
from the injury inflicted by them ; but were they to appear 
at shorter intervals, our forest and fruit trees would soon be 
entirely destroyed by them. They are moreover subject to 
many accidents, and have many enemies, which contribute to 
diminish their numbers. Their eggs are eaten by birds ; the 
young, when they first issue from the shell, are preyed upon 
by ants, which mount the trees to feed upon them, or destroy 
them when they are about to enter the ground. Blackbirds 
eat them when turned up by the plough in fields, and hogs 
are excessively fond of them, and, when suffered to go at 
large in the woods, root them up, and devour immense 
numbers just before the arrival of the period of their final 
transformation, when they are lodged immediately under 
the surface of the soil. It is stated that many perish in the 
egg state, by the rapid growth of the bark and wood, which 
closes the perforations and buries the eggs before they have 
hatched ; and many, without doubt, arc killed by their peril- 
ous descent from the trees. 
There are several other harvest-flies in the United States, 
the males of which are musical ; but their drums are con- 
cealed within little cavities in the sides of the first abdominal 
ring. One of these is found in Massachusetts, and, though it 
never appears in such great numbers as the preceding species, 
it is more common or more generally met with throughout 
the State. It may be called the dog-day harvest-fly, or 
Cicada canicularis (Fig. 88), from the circumstance of its in- 
variably appearing with the beginning of dog-days. During 
many years in succession, with only one or two exceptions, 
I have heard this insect, on the 25th of July, for the first 
time in the season, drumming in the trees, on some part of 
the day between the hours of ten in the morning and two 
in the afternoon. It is true that all do not muster on the 
same day ; for at first they are few in number, and scattered 
at great distances from each other ; new-comers, however, 
are added from day to day, till, in a short time, almost every 
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