1985] 
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frequency histograms, support the viewpoint of bimodal emergence 
and a univoltine life cycle. 
The population range diagram shows the wide range of head 
widths that occurred each month (Figure 3). Immature nymphs that 
were too small to be sexed are not represented in the diagrams. The 
largest head width for males was 2.9 mm, and for females 3.4 mm; 
both occurred in April. Size superiority exhibited by females is 
shown in Figures 2 and 3. 
Morphological Analysis. Results from the discriminant analysis 
of all B. Carolina popultions are presented in Figure 4. The first two 
canonical axes were responsible for 83.2 and 8.5 percent of the total 
dispersion, respectively. One hundred percent dispersion was 
obtained when four axes were utilized. The most influential charac- 
ters providing separation on the first axis, in order of increasing 
weight, were: mesothoracic leg femur length; body length; shield 
width; and mesothoracic leg tarsus length. Overlap of canonical 
coordinates for individuals of different geographical populations 
indicates that substantial morphological variation exists within 
populations. Canonical coordinates for populations on the first 
(horizontal) axis generally followed a north-south geographical 
cline. 
The light and dark colormorphs from Panther Creek showed 
extensive overlap, and a relatively high percentage of individuals 
were classified incorrectly between these two groups relative to the 
other groups in this analysis. This further indicated that one species 
of Baetisca nymphs exists in Panther Creek, rather than two species 
as was assumed at the onset of this study. 
Baetisca berneri nymphs from the holotype locality showed con- 
siderable morphological similarity to the Virginia and Tennessee 
populations of B. Carolina. 
Pescador and Berner (1981) noted morphological variation 
among geographical populations of B. Carolina nymphs. They 
reported that nymphs from the northern extension of their range 
have a broader mesonotal shield and shorter lateral spines than 
nymphs from the southern extension of their range. The nymphs 
from Panther Creek exhibited a broad mesonotal shield and short 
lateral spines. Additionally, it was observed in this study that 
nymphs from the northern extension of their range exhibited shor- 
ter genal spines on the head. 
