N. lewisi Habitats and Behavior 87 



years of the study permitted us to maintain variable water temperatures 

 equal to those observed at Site No. 1 (R=3°-24° C, x=16°C). Light sour- 

 ces were north-facing laboratory windows and overhead fluorescent fix- 

 tures. Light duration and intensity could not be controlled, but duration 

 was similar to normal seasonal day length. A red light was used for 

 some night observations. 



DESCRIPTION OF STUDY SITES 



Site No. 1 



Site No. 1, where we studied adult N. lewisi, was located on Little 

 River at Mitchell's Mill Pond State Park, northern Wake County. This 

 was the same site used by Fedak (1971) during his study of the same 

 species. Little River is a headwater stream in the Neuse River drainage 

 of northeastern North Carolina. The stream begins on the Piedmont 

 Plateau and confluences with the Neuse River just after crossing the 

 Fall Line Zone. 



Little River at Site No. 1 is a typical Piedmont stream; 30 percent 

 of the bottom and 8 percent of the banks are covered with granite 

 boulders and outcrops. The remainder of the stream bottom was sand 

 and fine gravel. The banks were steep, with a 3:1 or greater slope, and 

 consisted of sandy-clay soil. The banks were profusely pocked by bur- 

 rows of crayfish and other animals. On the high-energy side of the 

 stream the banks were undercut in a number of places, and burrows of 

 Castor and Ondatra were present in some. An average of 72 percent of 

 the main study area was shaded by the surrounding mixed deciduous 

 forest. Mean width of the stream at the control site for this area was 7 

 m, and mean depth was 1.2 m. The greatest depth recorded was 1.9 m, 

 although we estimated that water level may have reached a height of 2.4 

 m during severe flooding. The shallowest depth recorded at the control 

 site was 0.6 m. Water temperatures at the control site ranged between 

 8°C and 22° C during the spring and 1°C to 12°C during the winter. 

 The greatest change in water temperature between sightings (48 hr) was 

 5C°. Dissolved oxygen levels ranged between 4 ppm and 9 ppm (x=7.2 

 ppm). Turbidity ranged from 14 to 40 ftu (x=30.25 ftu). Mean non- 

 flood rate at the standard site was 4.9 cm/ second. 



Site No. 2 



Site No. 2, where we studied larvae, was in the Little River, 

 northwestern Johnston County, 12.8 km east of Site No. 1. This site lies 

 within the transitional Fall Line Zone between the Piedmont Plateau 

 and the Coastal Plain, as indicated by the lack of granite outcroppings, 

 presence of sandy soils, and paucity of large rocks in the river bottom. 

 Cypress trees, common along the river bank, were absent from the study 

 site itself. Twenty percent of the sandy bottom within Site No. 2 was 



