THE STATE ENTOMOLOGIST. 3S 



S. W. to Vinton, in Benton county; thence S. E., skirting the Iowa river, to 

 the Mississippi at a point in the northern part of Louisa county — thus em- 

 bracing about a dozen counties, or l-12th part of the State. In Illinois the 

 boundary line, in a general way, may be drawm from the jS". W. portion of 

 Mercer county, S. E. to the Illinois river at Peoria, W. along the Toledo, 

 Wabash and Western railroad. There seem to be detachments extending 

 further south, especially in the eastern portion of the State, and they oc- 

 curred as far south as Shelby county. In Indiana the line is not well de- 

 fined, but includes the extreme N. W. counties, extending as far south as 

 the Kankakee river. In Michigan it does not extend north as far as St. 

 Joseph on the Lake. 



As this insect can only appear in districts which were timbered or 

 planted to orchard 17 years ago, it follows that in such an extensive prai- 

 rie country as that within the limits indicated, the Brood must be very 

 much detached and scattered. 



They did not appear in the Pequea Yalley in Lancaster county. Pa. : 

 at least I have been unable to get any authentic record of the fact. 



From all I can learn no Cicadas appeared at Plymouth, Mass., a fact 

 which corroborates my view expressed in 1868, that the visit recorded by 

 Morton in 1633 was a premature one and that it was due in 1634 : 



BROOD \l.—Tredecim—lSnS, 1871. 

 In the year i871, being the same year as the preceding, and at iutei-vals of tliirteen years thereaf- 

 ter, they will, in all probability, appear in tlie extreme southwestern corner of Mississippi and in the 

 adjoining part of Louisiana. Br. D. L. Phares, ofXewtonia (near Woodville,) Miss., saysthat in IS.M, 

 they extended over most of Wilkinson and part of Amite counties, Mississippi, and East an West 

 Feliciana, La. He has liimself witnessed the appearance of this Brood during the years 1S32, 1845 and 

 1858, while it is distinctly remembered by aged people in liis neigliborliood as having also appeared 

 there in the years 180G and 1819. Dr. Smith gives their I'ange from tlie Mississippi river, east to a 

 ridge forty-Qve miles from the river that divides the State north and south, and north and south to 

 the boundaries of the State ; recording them as occurring in 1806, 'ID, '32, '45 and '58. 



This Brood also appeared last summer, and a few precursors were noiieed 

 in 1869, but none in 1870. I quote the following account of it from a 

 letter from Dr. Phares : " A few males began to appear about the 20th 

 of April. Not many of any kind came out till the 7th and 8th of May. 

 On those two days from 5 1-2 till 8 p. m., or about dark, they came forth 

 from the earth in vast numbers ; and in large numbers from that time for 

 ten days more — the last I noticed, issuing on the 18th of May and being 

 mostly of the smaller and sometimes darker colored individuals. Perhaps 

 three-fourths of those coming up on the 7th and 8tli of May were females. 

 They are now (May 22ad) in full song, and I notice, with others, that when 

 my large bell (412 pounds) is rung, the}^ sing with redoubled fury." 



Dr. Phares also sent me a large number of specimens, and measure- 

 ments to show that there is a variation of at least half an inch in the exjjanse 

 of the wings, and that the small dark form which has been named Cassinii is 

 connected with the larger normal form by infinite grades. He is more con- 

 vinced than ever that the small form cannot be a distinct species, and that 

 there should be no C. Cassinii recognized ; in which opinion I fully concur. 



The experience of the j)ast year furaishes nothing new beyond what I 

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