GILBERT: FISHES OF THE SUBGENUS LUXILUS


error. A reexamination of material recorded by Fowler (1922: 12;
1923: 11) from the Dan River, Virginia, and from the Neuse River
system, North Carolina, shows these specimens are Notropis albeolus.
 LIFE HISTORY AND ECOLOGY. Most of the following information
has been taken from Outten's (1957: 68-84) detailed study of this spe-
cies' life history.
 Notropis coccogenis is an inhabitant of the swift riffles and flow-
ing pools of medium to large upland streams. It occurs character-
istically in the middle to upper levels of water and prefers a bottom
composed of rocks and gravel.
 Mostindividuals attain maturity when 2 years old. At this time
they usually are about 75 mm SL, with the male averaging slightly
larger than the female.
 Outten observed spawning activity in the French Broad River
system of North Carolina from early June to middle July when the
water temperature was 680 or higher. This is somewhat later than
the period of spawning for N. cornutus and N. chrysocephalus in
Michigan. As the temperatures that N. coccogenis requires for breed-
ing do not appear appreciably different from those for cornutus and
chrysocephalus, the late spawning of coccogenis may be due to the
cooler stream temperatures at the high elevations of the Tennessee
uplands.
 Spawning takes place in rapids 6 inches or more in depth or in
more slowly flowing water up to 4 feet deep. In the shallow rapids
small groups of up to 8 or 10 males were observed to hold territories
over Hybopsis micropogon nests 21/2 feet long by 2 feet wide, with the
largest male occupying the upstream position. Occasionally one of
the females lingering in a group farther back in the pools moved for-
ward near a male. After remaining side by side a short time, they
settled to the bottom where, with considerable vibration of their
bodies, they spawned. This behavior is similar to that Raney (1940a:
7-8) observed for Notropis cornutas in New York.
 Age-growth studies show the main increase in length to take place
in the first and second years of life. During the first year males and
females show little size difference, but in the second and third years
males grow considerably more than females. Apparently little or
no difference in growth rates occurs during the fourth year.
 Counts of males and females in each age group show equal num-
bers of each sex present during the first year of life, but a higher
proportion of females among older fish (66.2 percent in the second
year of life, 76 percent in the third). This is paralleled by my ob-
servations on breeding populations of N. cornutus and N. chryso-


1964