West Virginia, and Pennsylvania about the last week of May, and 

 in Louisiana and Mississippi a fortnight or three weeks earlier. 



SEVENTEEN-YEAR BROOD XV — 1880-1897-1914. 



The 17-year brood of the periodical cicada which appeared in 

 1897 has been designated by the late Dr. C. V. Riley as Brood XV. 

 It is an old established brood, reported from Ohio as early as 1795. 

 So far as now ascertained it occupies a pretty compact territory, 

 embracing the southwestern corner of Pennsylvania, northern and 

 a portion of central West Virginia, and southeastern Ohio as far as 

 the Scioto River, thence extending in a broad strip northward through 

 the center of Ohio to Lake Erie. The brood is also reported from 

 Geauga and Lake counties, Ohio, and from Highland County, Va.* 



The remarkable distribution in Ohio may be due to the imperfect 

 record. As early as 1846 the late Dr. Gideon B. Smith records this 

 brood from "twelve counties in the eastern portion of Ohio," but 

 unfortunately fails to give the name of a single one. With our 

 increased experience only fifteen counties of Ohio can now be enum- 

 erated. Regarding the western limit of the brood in Ohio, a very 

 important statement by J. H. Niles, of Havana, Huron County, Ohio, 

 was published by Dr. Riley in 1885 and deserves to be repeated here : 



When the cicadas appeared in 1846, the question was raised whether they were 

 partial to any particular geological formation. The resiilt showed that they 

 occupied the conglomerate, the sandstone, and the slatestone formations of east- 

 ern Ohio, not the limestone formation of western Ohio. For instance, a line 

 drawn for the western edge of the black slate, from the city of Bucyrus, in Craw- 

 ford County, and the northwest corner of Huron Coimty and Erie County, to the 

 east of Sandusky Bay, marked correctly the western edge of the cicada of 1880. 



The brood nowhere appears on the eastern flank of the Allegheny 

 Mountains, nor does it extend westward beyond the center of Ohio. 

 Its territory, so far as ascertained, is not occupied by any other brood 

 of the periodical cicada except in Pennsylvania and some adjacent 

 counties of West Virginia, so that in the majority of the counties 

 enumerated below the cicadas appear only once every 17 years. 



Brood XV is always preceded by one year by the 17-year Brood 

 XIV but this is known only from States west of the Mississippi River, 

 so that no relationship seems to exist between these two broods. 

 Brood XVI which appears always one year later than Brood XV is 

 known from a number of localities both east and west of the terri- 

 tory occupied by Brood XV, but these localities are so scattered and 



* The latter locality is based upon a single record and requires confirmation. 

 In his first Missouri rei>ort Dr. Riley mentions Lewis County, Va., which is 

 changed to Lewis County, Ky., in Bulletin 8 (first series) of the Division of Ento- 

 mology. It should be Lewis County, W. Va. , the authority being the impub- 

 lished "Register" of Dr. G. B. Smith which was written before West Virginia 

 became separated from Virginia. 



