1975] 
Tarter , Watkins, & Little — Nigronia 
85 
Table 1. Seasonal head widths (mm) of larval size classes of N, fas- 
ciatus, Hisey Fork, Cabell Co., W. Va. 
Size 
Classes 
(Year of 
Fall 
Winter 
Spring 
Summer 
Hatching) 
1970 
x— 5.3 
(4.5-6.2) 
x — 5.5 
(4.9-5. 8) 
PUPATED 
N = 41 
N — 27 
1971 
x — 3.S 
x 1 
II 
Ci 
x = 4.7 
x— 5.3 
(2. 5 -4.4) 
(2. 5-4.7) 
(3. 9-6.0) 
(4.7-6. 0) 
N = 35 
N — 30 
z 
II 
to 
0 
N = 22 
1972 
x = 1.5 
x = 2.0 
x — 3.3 
x= 3.8 
( 1. 3-2.0) 
(1.7-2.2) 
(3.0-3. 5) 
(2.3-4.6) 
1973 
N — 4 
N =: 2 
N = 5 
N — 15 
x = 0.8 
(0.8) 
N — 10 
stream. The mean head width of larvae at the end of the first year 
of development (1972) was 3.8 mm (Table 1 and Fig. 2). After 
the 2nd year of development (1971), the mean head width was 
5.3 mm (Table 1 and Fig. 2). At the end of the 3rd year (1970), 
just prior to pupation, the mean head width was 5.5 mm (Table 1 
and Fig. 2). 
Larval head width demonstrated seasonal changes in growth 
(Fig. 2). The greatest growth rate (69.7%) of the larval popu- 
lation, occurred from winter to spring in the 1972 size classes. This 
development coincided with the greatest seasonal changes in water 
temperature, 5.6 C and 16.0 C, winter and spring, respectively. 
Pupal Stage. — One pupa was collected in the spring (April 27). 
It was found under a flat rock (ca 45 cm in diam) in an earthen 
cell 30 cm from the stream. Based on field observations of the first 
adult, pupation lasted approximately 21 days. 
Neunzig (1966) reported that N. fasciatus, in Nature Trail 
Creek, North Carolina, started pupation around May 5 and reached 
a peak the following week. The pupae were located under moss in 
earthen cells about 6-12 inches from the creek. Minshall (1968) 
noted that N. fasciatus from Morgan’s Creek, Kentucky, pupated in 
the early spring (April). 
