--------------------------+-----+-----+-----+-----+-----+-----+-----+---- [Illustration: PLATE 19 Fig. 1. Head of hatchling blue racer, dorsal view, September 1962, approximately × 3. Fig. 2. Head of hatchling blue racer, lateral view, September 1962, approximately × 3. Fig. 3. Head of yearling male blue racer, lateral view, August 1, 1961, a little less than twice natural size. Fig. 4. Head of adult male blue racer, lateral view, July 16, 1961, approximately × 2. All three snakes from Rockefeller Experimental Tract, Jefferson County, Kansas.] [Illustration: PLATE 20 Fig. 1. Abandoned limestone quarry on a hilltop of southward exposure on The University of Kansas Natural History Reservation, in late autumn of 1951. The crevices along the base of the ledge provided favorite hibernating sites for blue racers. Fig. 2. Hatchling blue racer and eggshell from which it had recently emerged, in early September, 1962; × approximately 1-2/3.] [Illustration: PLATE 21 Fig. 1. Wire funnel trap set at base of hilltop limestone outcrop in a spot strategically located for interception of blue racers searching for deep crevices in which to hibernate, October 15, 1949. Fig. 2. Large clutch of 21 blue racer eggs, recently plowed out, at Harold Brune farm, Jefferson County, Kansas, July 10, 1962.] [Illustration: PLATE 22 Fig. 1. Habitat of blue racer, blue-stem prairie on Botany Bluff at northwest corner of the University of Kansas Natural History Reservation, looking south. Trees and brush in background are along limestone outcrop at top of slope. Mowed area in foreground is southwest corner of Rockefeller Experimental Tract, a privately owned farm at the time this photograph was taken in the summer of 1951. Fig. 2. Habitat of blue racer, blue-stem prairie on south slope of Botany Bluff, looking north along west edge of the Reservation, summer of 1951. By 1962, with exclusion of fire, and protection from mowing, prairie vegetation had largely disappeared from this slope, and had been replaced by trees and brush. As a result of these successional changes racers no longer found this slope a suitable habitat in summer, but they continued to resort to the hilltop rock outcrop to hibernate in autumn.]