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Show Knowlton: 1937] Control of the Beet Leafhopper in Utah 133 Table 8. Data indicating the seasonal importance of Uta s. stansburi ana as a predator of E. tenellus in Utah areas among com mon host plants of the beet leafhopper, 1930 to 1935, inclusive. . Month Total No. No.lizards lizards taken containing E. tenellus No. E. tenellus contained per stomach , Adults Nymphs Total Average March 11 3 3 0 3 1.00 April 28 3 3 0 3 1.00 May 102 11 31 6 37 3.36 June 238 8 15 1 16 2.00 July 203 50 172 78 250 5.00 August 596 227 905 290 1195 5.26 2193 1413 3401 5355 8756 6.19 October 639 526 838 4826 5664 10.77 November 11 8 22 20 42 5.25 4021 2249 5390 10576 15966 September Totals I 7.09 The Sagebrush SWiift.-The sagebrush swift, Sceloporus graciosus gra ciosus (Baird and Girard), occurs in large numbers in many sagebrush and rabbit brush sections and in most of the Utah canyons and foothills, in which studies have been made. Where this small lizard occurs in abundance near plants harboring beet leafhoppers, it is not uncommon to find the lizards in gesting these small insects. As a rule, immature swifts consumed a higher percentage of small insects, including tenellus, than did the large, mature specimens. However, all sizes of swifts were found to have fed recently upon beet leafhoppers. A study of Table 11 shows that 80 lizards of the 221 taken beet leafhopper host plants, had recently eaten tenellus, the number being 158 adults and 139 nymphs, or a total of 269 specimens still in recognizable condition. This would be an average of 3.7 tenellus per stom ach for those containing beet leafhoppers. Data in Table 9 indicate that 36.2 per cent of the sagebrush swifts, collected from among host plants of the beet leafhopper in the 27 localities listed, had ingested tenellus recently enough that the leafhoppers were still in recognizable condition among the stomach contents when the lizards were collected. The sagebrush swift occurred upon desert breeding areas of the beet leaf hopper in populations estimated at 100 per acre at the abandoned townsite of Hardup, and near Snowville, in Boxelder County, 25 to SO per acre in parts of Skull Valley south of Iosepa, and approximately 100 per acre near Orr's Ranch, at the south end of Skull Valley, in Tooele County. .Because these among or near lizards appear to spend most of their time among the brush, feeding upon in- |
