1985] 
Schmidt & Tarter — Acroneuria carolinensis 
397 
Fecundity was determined by direct egg count. Eggs were dis- 
sected out from 19 adults. They were placed in a Syracuse watch 
glass and counted under a binocular dissecting scope. Regression 
analysis was used to determine the relationship between total body 
length and number of eggs produced. A correlation coefficient (r) 
was calculated to determine the strength of the relationship. 
The diameter and length of 125 eggs from five adults were mea- 
sured using an ocular micrometer in a binocular dissecting scope. 
Eggs were measured to the nearest 0.01 mm. Average egg size was 
calculated. 
Results and Discussion 
Stream environment. The mean water temperature at Panther 
Creek during the study period was 8.3 C. The temperature ranged 
from 0.0 in January to 16 C in June. During emergence studies, a 
high temperature of 17 C was recorded on 8 June 1984. 
Dissolved oxygen was high, ranging from 7 to 13 mg/1 (X = 9.4 
mg/1). Carbon dioxide ranged from 10 to 85 mg/1, with a mean of 
61.5 mg/1. Alkalinity ranged from 0.0 to 102.6 mg/1 (X = 29.9 mg/1) 
during 1982, according to Pettry (1983). Total hardness ranged from 
34.2 to 224.9 mg/1 (X = 122.8 mg/1). The pH had a mean value of 
6.9 and ranged from 6.3 to 7.2. 
Length-frequency histograms. Length-frequency analysis indi- 
cated a two-year life cycle (Figure 1). Body length ranged from 3.5 
to 26.0 mm. The largest naiads were collected in February, April 
and May. Larger naiads were absent following the 20 May collec- 
tion, when emergence had occurred. There was approximately an 1 1 
week egg development period before recruitment of the new age 
class. The smallest and earliest naiads were first collected in late 
August. The existence of a 6 mm naiad in January suggested some 
evidence that a three-year life cycle may be possible. Absence of 
additional naiads of this size could have been due to the larger mesh 
size dredge used during the winter collections. 
Harper and Magnin (1969) suggested three-year life cycles for A. 
abnormis and A. lycorias. They also indicated that the number of 
naiads collected was too small to make a definite conclusion. Shel- 
don (1969) reported a life cycle of three years for Calineuria Califor- 
nia at an elevation of 2200 m. Heiman and Knight (1975) and 
Siegfried and Knight (1978) both suggested a two-year life cycle at 
