256 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



Subsequent measurements show the median spots of the males from 

 Indian Gap to be as much as 70 percent as wide as the metatergite; 

 at Soco Gap the spots merge with those of the paranota forming 

 complete bands. Smaller median spots prevail both north and south 

 away from the central part of the Smokies, their width only 30 percent 

 of the metatergite width in the vicinity of Mount Sterling, at Chimneys 

 Campground, and in the Unicoi range south of the Little Tennessee 

 River. 



Specimens from the Unicois are not entirely typical of ducilla; 

 they have lighter colored pleurites (the anal valves quite dark, how- 

 ever), and the tibiotarsal spur is variously developed in 4 of 8 males 

 examined. The body form remains narrow, however; it averages 

 21.7 percent in 6 males from Little Haw Knob and 22.2 percent in 2 

 males from Stratton Gap. Whether this segment of ducilla has been 

 isolated from that of the Great Smokies by the gorge of the Little 

 Tennessee or has evolved independently from a common ancestral 

 stock in the Nantahala region remains to be established. There 

 would seem to be little chance for genetic exchange between the two 

 isolated populations at the present time. 



Remarks: One of the most interesting aspects of the taxonomy 

 of ducilla lies in the fact that to the east and southeast it grades almost 

 imperceptibly into georgiana in all its diagnostic characters. To the 

 west, fairly typical georgiana occurs in Cades Cove at the base of the 

 Smokies, and ducilla in the same region attains its smallest and 

 slenderest body form. No intergradation has been detected here, 

 and I doubt that it occurs, the two forms being so radically different 

 in size and shape. 



I hope that someone having the opportunity for extensive studies in 

 the Great Smokies will be able to work out the relationships of the two 

 local forms of Cherokia there, particularly in the region between New- 

 found Gap and Cades Cove, and along the main ridge between Cling- 

 man's Dome and Gregory Bald. 



Despite having collected ducilla at several places and different times, 

 I have learned very little of its life history and activity. The mating 

 season is somewhat later than that of georgiana) no mated pairs were 

 collected until August 4, 1958, when some were taken at Indian Gap. 

 Here specimens taken singly paired up while being carried in my hand, 

 and remained clasped in a jar of humus overnight. No doubt the 

 brevity of the warm season at such high elevations influences the 

 maturation of individuals and postpones the mating activities. 



Confinement of energetic males from Indian Gap with females of 

 georgiana taken near Toccoa, Georgia, resulted in nothing. The males 

 were about 2 mm. narrower, and probably would have been unable to 

 secure a suitable grip even had pairing been attempted. 



