INJURIOUS AND BENEFICIAL INSECTS. 253 



of the 'Naturalist' a request for twigs oiodk wliich liad been 

 stung by the so-called seventeen-year locust, I take the lib- 

 erty of sending you twigs from eleven different varieties of 

 trees in which the females have deposited their eggs. I do 

 this to show that the insect seems indifferent to the hind of 

 wood made use of as a depository of her eggs. These were 

 gathered July 1st, in about an hour's time, on the south hills 

 of the 'Great Chester Valley,' Chester County, Pa. No 

 doubt the number of trees and bushes might be much increased. 

 The female, in depositing her eggs, seems to prefer well- 

 matured wood, rejecting the growing branch of this year, and 

 using last year's wood and frequently that of the year before, 

 as some of the twigs enclosed will show. An orchard which 

 I visited was so badly ' stung ' that the apple-trees will be 

 seriously injured, and the peach-trees will hardly survive 

 their treatment. Instinct did not seem to caution the animal 

 against using improper depositories, as I found many cherry- 

 trees had been used by them, the gum exuding from the 

 wounds, in that case sealing the eggs in beyond escape. 



"The males have begun to die, and are found in numbers 

 under the trees ; the females are yet busy with their peculiar 

 office. The length of wood perforated on each branch varied 

 from one to two and a half feet, averaging probably eighteen 

 inches ; these seemed to be the work of one insect on each 

 twig, showing a wonderful fecundity. 



"The recurrence of three 'locust-years' is well remembered 

 in this locality — 1834, 1857, and 1868. There has been no 

 variation from the usual time, establishing the regularity of 

 their periodical appearance." 



As regards the time and mode of hatching, Mr. S. S. 

 Rathvon of Lancaster, Pa., contributes to the same journal 

 some new and valuable facts, which we quote : "With refer- 

 ence to the eggs and young of the seventeen-year cicada, 

 your correspondent from Haverford College, Philadelphia, is 

 not the only one who has failed to produce the young by 

 keeping branches containing eggs in their studios. I so failed 

 in 1834 and 1851, and indeed I have never heard that any 

 one has succeeded in that way, who has kept them for any 

 great length of time. In the brood of 1868, the first cicadas 

 appeared here in a body, on the evening of the second day of 



