196 INJUKIOUS INSECTS 



operations, has appeared as full of holes as a honey-comb. 

 Within about a fortnight after their final transformation 

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

 weeks the whole generation becomes extinct. 



They are 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 thorn, or destroy them 

 when they are about to enter the ground. Blackbirds 

 eat them when turned up by the plow 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 are hatched; and many, without doubt, 

 are killed by their perilous descent from the trees. 



Such are the general habits of this remarkable insect 

 which now, and probably has for ages, passed seventeen 

 years of its life hidden in the soil, and at stated periods 

 has appeared for a short season of life above ground. A 

 most elaborate account of the habits of this Cicada will 

 be found in the First Missouri Keport (1868), in which 

 the important discovery is announced that there are races 

 which complete their career in thirteen years; while no 

 differences have been found between the Thirteen-year 

 and Seventeen-year Cicadas, other than in the time of 

 their appearing, yet some entomologists give them as 

 distinct, and the Thirteen-year Cicadas are, for conven- 

 ience called 0. tredecim, Riley. This form is confined to 

 more southerly localities than the other. While the Sev- 

 enteen-year Cicada completes its round in that num- 

 ber of years, it is not due all over the country on the 



