rKMloi) OF KMKK(}KN('K. S9 
Doctor Pharos, wi-iiinjj; of {\\o occurrcMicc of 1)I(k)(1 XXII in ls71, 
states tliat a ivw mnhvs l)(>u:an to apjx'ar about the _*()ili of Aj)iil, hut 
that the hulk of the brood did not cincr^e until the 7lli and mIi of 
^hiy, wliou {\\v\ eaiiie foi'th from the eaiih in \ a>t luiinlxM^. continii- 
iiii^ to iMiUM-t:;e in (hininisliinix nunihers until the istli of Mji\. It will 
be reinenihered that this is the most southern of all the hroods- l\in«r 
in the southwest eoi'nei" of Mississij)|)i and th(> adjoininir parts of 
Louisiana. 
Mr. John Hart ram, writiniz; of tlu^ hrood appeai'in^^ in 17 1!), states 
tliat in th(> ncM^lihorhood of Phiiadcdphia an ahundaiiee of these 
iiiseets whieli liad just escaped from then* skins was observed on the 
niornhit]; of May 10 and that they continued to issue in ^reat numheis 
for a week or more, be<2:innin<2: to sing on the 13tli and to ()vi])osit on 
the lOth, and disappearing altogether by the 8th of June. 
In the great brood year of 1868 Professor Riley noted tliat in tlic 
vicinity of St. Louis ''they commenced to issue on the 22d of May, 
and by the 25th of the same month the woods resounded with tlie 
rattling concourse of perfect insects." At Washington, D. C, in the 
Cicada year 1885, scattered individuals appeared on May 23, and they 
issued, perhaps, most abundantly on the night of the 27th. Those 
emerging within the city were somewhat earlier in appearance than 
was the case in the neighboring woods across the Potomac in Virginia, 
probabl}' for the same reason that the trees in the city put out their 
fohage a little earlier than in the near-by woods. 
Mr. Davis, writing of Brood II as it appeared in 1894 on Staten 
Island, New York, sa3^s that as early as May 19 many cicadas had 
emerged, the first individuals of the swarm being noted six or seven 
days earlier. 
Mr. A. W. Butler, writing of the brood appearing in 1885 in Frank- 
Lin County, Ind., says that while in a few localities individuals were 
seen as early as May 28, in other places not distant they did not 
emerge until June 4, and later. 
Mr. Hopkins made a careful study of the dates of emergence in West 
Virginia in 1897 in connection with Brood V, and found very consid- 
erable variation in time of appearance both between the northern and 
southern borders of the brood and between the lowest and liighest ele- 
vations within the area covered by the brood. For the former a differ- 
ence of nearly two weeks was indicated by the records, and iov the 
latter a difference of nearly four weeks. Tliis variation, he says, 
appears to be due to the difference of climate between the northern 
and southern sections and ])etween low and higli elevaticms, in the 
former eas(^ amounting to -V. degrees and in tlie latter to over 10 
degrees in average summer temperature. lie deduces from liis obser- 
vations, as a general rule, that there is about three and one-half da3"s 
difference in tlie time of the first general appearance- of the Cicada for 
