216 
HEMIPTEKA. 
noitre, but descending again on the occurrence of cold or wet 
weather. 
During their temporary residence in these burrows near 
the surface, the Cicada grubs, or more properly pupae, for 
such they are to be considered at this period, though they 
still retain something of a grab-like form, acquire strength for 
further efforts by exposure to the light and air, and seem then 
only to wait for a favorable moment to issue from their sub- 
terranean retreats. When at length this arrives, they issue 
from the ground in great numbers in the night, crawl up the 
tranks of trees, or upon any other object in their vicinity to 
which they can fasten themselves securely by their claws. 
After having rested awhile, they prepare to cast off their 
skins, which, in the mean time, have become dry and of an 
amber color. By repeated exertions, a longitudinal rent is 
made in the skin of the back, and through this the included 
Cicada pushes its head and body, and withdraws its wings 
and limbs from their separate cases, and, crawling to a little 
.distance, it leaves its empty pupa-skin, apparently entire, still 
fastened to the tree. At first the wing-covers and wings are 
very small and opaque, but, being perfectly soft and flexible, 
they soon stretch out to their full dimensions, and in the 
course of a few hours the superfluous moisture of the body 
evaporates, and the insect becomes strong enough to fly. 
During several successive nights the pupae continue to 
issue from the earth ; above fifteen hundred have been found 
to arise beneath a single apple-tree, and in some places the 
whole surface of the soil, by their successive operations, lias 
appeared as full of holes as a honeycomb. In Alabama the 
species under consideration leaves the ground in February 
and March, in Maryland and Pennsylvania in May, but in 
Massachusetts it does not come forth till near the middle of 
June. Within about a fortnight after their final transforma- 
tion they begin to lay their eggs, and in the space of six 
weeks the whole generation becomes extinct. 
Fortunately these insects are appointed to return only at 
