10 



every 65 or 78 years at some part of the Great 

 Southern Brood's total range in Ilhnois, but only once 

 every 221 years at each specific locality. 



A limited number of specimens of this brood were 

 collected in the twin cities of Champaign- Urbana in 

 1959 and in 1972. They were taken even in those 

 parts of the cities which were originally prairie or were 

 cultivated land less than 25-.50 years previously but 

 which are now studded with trees. Moderate singing 

 also was heard by competent observers in both of 

 these years. It would seem, therefore, that colonizing 

 cicadas succeeded in expanding their range at least a 

 few miles into new parklands and tliat the population 

 level for survival need not be extremely high. 



Although bird populations are low in some parts 

 of these cities, where birds are present, cicadas are 

 eagerly sought. In one instance a dozen live cicadas 

 were placed on a hedge in Urbana near a bird-feeding 

 tray. Within 1 minute a blue jay appeared and seized 

 one of the sluggish cicadas. Shortly, this jay returned 

 and was joined by another. AU, or at least 11, of 

 the cicadas were quickly taken by the jays; the fate 

 of the last cicada was not determined in the con- 

 fusion of the jays' visits to the hedge. Other birds, 

 including hawks, were found to have fed heavily on 

 these cicadas in southern Illinois (Dr. R. R. Graber 

 personal communication 1972). 



Unpublished reports by Dr. G. W. Bennett indi- 

 cate that game fish benefited from the abundance of 

 this brood in 1972. Fishes at Fox Ridge State Park, 

 Coles County, fed voraciously on these insects. Cicadas 

 at that site weighed from about V2 gram to nearly a 

 full gram. 



The Northern Illinois Brood (Marlatt's XIII) 



The Northern Illinois Brood has a 17-year cycle, 

 and its most recent emergence was in 197.3. Possibly 

 because a wet, cool spring delayed the emergence, 

 the earliest 1973 records of this brood (Fig. 4) were 

 not taken until May 31 (Tazewell and Sangamon 

 counties) and June 2 (Cook County). Singing was 

 heard in Tazewell County at the end of May and in 

 Jo Daviess, Cook, and Lake counties as late as June 

 20. 



This brood occurs primarily on the Wisconsin 

 glacial drift area except for areas in east-central 

 Illinois. These east-central Illinois regions are occu- 

 pied by the 13-year Great Southern Brood. Several 

 competent observers noted the absence of this brood 

 from the Zion sand areas in Lake C^oxnity, and m\- 

 associates and I failed to find any specimens in the 

 sand areas of Iroquois, Mason, and Lee counties. 



The Northern Illinois Brood ranges south to Car- 

 penter Park, north of Springfield, and to Petersburg. 



Fig. 4. — Distribution of the Northern Illinois Brood 

 (Marlatt's XIII) of periodical cicadas in Illinois. Black 

 dots indicate positive records of adult specimens, skins, 

 holes in the ground, flagging tree branches, or singing. 

 Circles imlicatp negative records in areas carefully searched. 



\\'oods south of Springfield and woods near Me- 

 chanicsburg showed no e%'idence of cicadas (sped- 

 niens, singing, skins, or holes in the ground). During 

 the preceding year, 1972. the Great Southern Brood 

 emerged in these woods {A. L. Koelling personal com- 

 munication 1973). At the Springfield and Mecliani(.> 

 burg area, at least, this brood and the 13-\oar Groat 

 Southern Brood probablv emerged siniultaneouslv in 

 1582 and 1803, and will do so again in 2024 and 2245. 



The persistence of this brood in old parts of cities 

 was noted in Chicago and Rockford. Mrs. Barbiua 

 Fell noted a few skins in her back yard at S19 North 



