EEPORT OF THE ENTOMOLOGIST. 251 



Tennessee and the Mississippi Kivers. In the southern part of the State 

 there is an eastward extension of the brood across the Cumberland Si ver, 

 find this eastward extension is still more marked in Tennessee, where 

 the Cicadas have been reported so far east and south as beyoiid Xasli- 

 ville. The entirely isolated locality, or rather group of localities in 

 Georgia has already been referred to on page 250. The locality in Kan- 

 ©as formerly referred to this brood must be stricken off (see p. 247). 



OcograpJiical distrihution of Brood XXII. — This is by far tbe largest 

 of the fourteen broods of the 17-year race of the Periodical Cicada 

 known to exist in the United States, and it is only equaled in extent by 

 the 13-year Brood XYIII (1881 and 1894). It extends from the Atlantic 

 Ocean to middle Illinois and Wisconsin, and, reaching in its northward 

 extension to beyond the forty-third parallel in Michigan and Vfiscon- 

 sin, it nearly attains, southward, the thirty-fourth parallel in Georgia. 

 However, this immense area is by no means evenly occupied by the 

 Cicada, and a glance at our map will at once show a very striking feature 

 in its distribution, viz : It is divided into two large and sharply divided 

 bodies or branches. Detached areas of smaller or larger extent are of 

 frequent occurrence in the geographical distribution of the various 

 broods, but in no other brood is the separation so stiikiog as bere. The 

 belt separating the two branches, and in which consequently the Cicada 

 did not appear this year, is formed by the following territory: Western 

 and northern Pennsylvania, eastern half of Ohio, West Virginia west 

 of the Alleghanies, central and eastern Kentucky, and a large portion 

 of Tennessee. 



The Eastern branch commences at Long Island,* New York, and, fol- 

 lowing a southwestern course, extends in small detached areas through 

 middle New Jersey until, in Pennsylvania, we meet the compact main 

 body of the brood which occupies the southeastern third of Pennsyl- 

 vania, the northern half of Delaware, the whole of Maryland (except- 

 ing the southern half of the peninsula between the Potomac and the 

 Chesapeake Bay and the corresponding portion of what is known as 

 the Eastern Shore), adjacent counties of West Virginia and the northern- 

 most counties of Virginia. From this point southward an extremely 

 interesting feature of the brood has been elucidated by this year's in- 

 vestigation, viz, that the Cicadas are entirely confined to the mountain- 

 ous region, appearing nowhere in the open country east of the Allegha- 

 nies. Our records are not complete enough to decide whether the 

 Cicadas occupy the valley of Virginia and adjacent portions of the 

 Carolinas in a more or less complete bodj' or in detached areas, but we 

 are inclined to believe that the latter case will prove to be' correct. At 

 any rate, in eastern Tennessee and northern Georgia, from which sec- 

 tions the records are more plentiful, the distribution of the Cicada 

 seems to be governed by topographical features, the nature of which is 

 still obsure, and the Cicadas are reported from numerous localities ap- 

 pearing either in strips, bordered by mountain rauges or streams, or in 

 areas of smaller or larger extent with no definite natural boundaries. 

 In Georgia the dividing line between the region occupied by this Brood 

 XXII and that of Brood VII is by no means vrell ascertained, as already 

 stated on p. 250. In Tennessee the Cicadas were reported on the mount- 

 ains west of Chattanooga, thus reaching the northeast corner of Ala- 

 bama. For this reason we are inclined to believe that the Cicadas re- 



• The more northern localities given in our previous records, viz, Fall River, Mass., 

 Eutland, Vt., and Rochester, N. Y., were not confirmed by this year's investigation, 

 and have, therefore, been stricken off. 



