216 HEMIPTERA. 



noitre, but clescendinD- again on the occun'ence 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 grub-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 

 trunks of trees, or upon any other object in their vicinity to 

 Avhich 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 

 fistened 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 fidl dimensions, and in the 

 course of a few houi'S the superfluous moisture of the body 

 evaporates, and the insect becomes strong enough to fly. 



During several successive nights the puj)a3 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, has 

 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 

 jNIassachusetts it does not come forth till near the middle of 

 June. Within about a fortnio;ht after their final transforma- 

 tion they begin to lay their eggs, and in the space of six 

 Aveeks the whole generation becomes extinct. 



Fortunately these insects are appointed to return only at 



