204 EXPERIMENT STATION. [Jan. 



northwest in Ohio, embracing the southwestern corner of the State and 

 the northwestern portion of Kentucky, and then upward through south- 

 western Indiana, ending in central Illinois. 



1849. (Riley, XX.) Brood VIII. 

 Dukes. 1017. 



' Occurrence. 



Martha's Vineyard : 15 square miles of Central Plains, 1833 to 1900. 



This is one of the smallest broods and covers a quite compact 

 territory, the greater part of which lies in central and western 

 Pennsylvania and eastern Ohio, with a few localities in north- 

 ern West Virginia and southwestern New York. Two widely 

 separated swarms listed from Illinois and South Carolina are 

 extremely doubtful, and both are j)i'obably based on confusion 

 of some of the annual species with the periodical cicadas. The ' 

 Massachusetts part of this brood, occurring in Dukes, is also 

 widely separated, but is fully established and has been well 

 recorded since the time of Harris. Dr. Harris records their 

 first appearance in Martha's Vineyard in 1833, while Smith's 

 " Register " gives the next in 1819, and Geo. H. Luce of West 

 Tisbury, Mass., states that they were there in 1849-66-83 and 

 1900. In the "American Naturalist," October, 1883, G. E. 

 Bessey writes : — 



While driving across " the plains " of the central part of Martha's 

 Vineyard, in the last few days of June of this year, I observed large 

 numbers of the periodical cicadas. The serub-oaks, which here cover the 

 whole ground, were literally alive with them. The insects were confined 

 to a narrow belt, not exceeding half or three-quarters of a mile in width 

 and of unknown length. 



^&' 



At its last appearance, in 1900, it seemed desirable to ascer- 

 tain the accuracy of previous observations and learn whether 

 this isolated colony was holding its own. Through the kindness 

 of Mr. Luce it was learned that " the brood was a well-known 

 one and as much in evidence as ever. They were quite numer- 

 ous, but seemed to confine themselves to a district known as the 

 plains district, — a tract of land covered with scrub-oak and very 

 lightly wooded. They could be heard more than a mile, making 



