18 ENTOMOLOGICAL SOCIETY 



of growth and transformation which has been described else- 

 where. That a successful outcome was sure to be had in this 

 experiment was demonstrated in the early spring of 1906, the 

 year for the appearance of this brood, the ground about the 

 planted trees exhibiting many of the exit holes of the insects 

 which are made to the surface long before the insect emerges. 

 These holes under certain trees were so numerous as to indi- 

 cate the emergence of thousands of cicadas. Under one tree 

 a count and estimate were made of more than 5,000 openings, 

 and under other trees the openings ranged from a few hun- 

 dred to from one to three thousand. The actual emergence 

 took place between May 14 and 21. The writer visited the 

 grove on two evenings, and witnessed the issuance of numbers 

 of cicadas and collected some specimens. In spite, however, 

 of the considerable number of cicadas which emerged, none 

 was seen on the trees during the days and weeks following. 

 Each morning about the planted trees would be found a con- 

 siderable group of blackbirds, which evidently had been feast- 

 ing on the newly-issued cicadas. The cast pupal shells were 

 numerous on the trunks of the trees and especially on the foli- 

 age, and also on the ground, but scarcely a single cicada 

 escaped the sharp eyes of these birds, and the characteristic 

 song was not heard during June in this grove, although thou- 

 sands of adults had come forth. 



At none of the examinations were cicadas of this brood 

 found under any of the trees except where eggs had been dis- 

 tributed, and no emergence holes appeared under other trees. 

 The record from the planting to the emergence of this insect 

 is therefore complete, and gives the demonstration by actual 

 transfer and breeding record of the long period of the 17-year 

 brood, a demonstration which, as indicated at the outset, was 

 entirely unnecessary to show the correctness of this extraordi- 

 nary hypogeal term. 



The absolute failure of these insects to establish themselves 

 when planted in such enormous numbers, even when the under- 

 ground period had been successfully passed, owing to the re- 

 lentless onslaught of birds, is a striking illustration of what is 

 happening every year with the different broods in nature, 

 especially in thinly forested regions, and accounts for their 

 great reduction in numbers and the practical disappearance of 

 many local swarms formerly abundant. It also shows that 

 there may be emergences in considerable numbers without 

 their being reported, unless some observer chances on a pupal 

 shell or notes the exit holes in the ground about the trees, and 

 hence the little value of a negative report as opposed to a posi- 

 tive one. 



