May, 1953 
Abdominal segments 2-6 white, extensive 
black tracheal outlines at each  spiracle; 
apical segments brown; genitalia and caudal 
filaments white; genitalia of the intercalaris 
type, with a papillate projection at meso- 
apical angle of first forceps segment, second 
segment conical, and fourth segment slightly 
longer than wide. 
Holotype, male.—Richmond, Illinois, at 
light, June 24, 1938, B. D. Burks. Specimen 
in alcohol. 
Paratypes.—Same data as for holotype, 
24. Specimens in alcohol. 
15. Baetis pluto McDunnough 
Baetis pluto McDunnough (1925a: 218). 
Matve.—Length of body and of fore wing 
4.5 mm. Head and thorax dark brown; legs 
yellow, with femora somewhat darker yel- 
low; stigmatic crossveins of each fore wing 
anastomosed ; hind wing, fig. 278, with third 
longitudinal vein relatively long. Abdominal 
tergites 2-6 dark red-brown, with only an- 
terior and lateral margins lighter in color; 
genitalia, fig. 295, tinged with brown and of 
the intercalaris type, with mesoapical papilla 
of first forceps segment wanting; caudal fila- 
ments white. 
Known from Ontario and Quebec. 
16. Baetis levitans McDunnough 
Baetis laevitans McDunnough (1925a: 215). 
Baetis levitans McDunnough (1925a:216). 
This species differs from pluto only in that 
the thorax is chestnut brown, the hind wing, 
fig. 279, usually has fewer marginal inter- 
calary veins and a shorter third longitudinal 
vein, the abdominal tergites 2-6 are yellow, 
with a brown, transverse streak at the pos- 
terior margin of each, and the genitalia are 
white. 
Known from New York, Pennsylvania, 
and Quebec. 
17. Baetis flavistriga McDunnough 
Baetis flavistriga McDunnough (1921:120). 
Mate.—Length of body 4.5 mm., of fore 
wing 5.0 mm. Head gray-brown, with face 
black and antennae dark smoky gray. 
Thorax dark gray-brown, with a greenish 
cast and yellow markings; legs white, fe- 
mora shaded with yellow; each hind wing 
Burks: THE Mayr ties or ILtrNois 133 
with third longitudinal vein well developed, 
one-half as long as wing, and a single mar- 
ginal intercalary vein usually present be- 
tween veins 2 and 3. Abdominal tergites 
2-6 light yellow-brown, apical tergites dark 
yellow-brown, faint black spiracular mark- 
ings present; genitalia and caudal filaments 
white. 
Known from New York, Ontario, and 
Quebec. 
18. Baetis cingulatus McDunnough 
Baetis cingulatus McDunnough (1925a: 216). 
Mate.—Length of body 5.0 mm., of fore 
wing 5.5 mm. Head very dark brown. 
Thorax dark gray-brown, with small, vari- 
able tan or yellow markings; legs light yel- 
low, with all femora shaded with brown; 
each hind wing with third longitudinal vein 
well developed, one-half as long as wing, 
marginal intercalaries absent or extremely 
faint. Abdominal tergites 2-6 yellow, with 
a narrow, bright red-brown, transverse 
stripe at posterior margin of each, apical 
tergites darker red-brown; genitalia and 
caudal filaments white. 
Known from New York, Pennsylvania, 
and Quebec. 
19. Baetis anachris new species 
This species is similar to rusticans in that 
the hind wing is relatively broad and has 
three longitudinal veins, abdominal tergites 
2-6 are brown, and the genitalia are of the 
intercalaris type, having the mesoapical pa- 
pilla of the first forceps segment present. 
The two differ in that the stigmatic cross- 
veins of the fore wing in anachris are nu- 
merous and anastomosed, while there are 
only four to six nonanastomosed stigmatic 
crossveins in rusticans; abdominal sternites 
2-6 in anachris are white, while they are a 
light smoky gray in rusticans. 
Matve.—Length of body 4.5 mm., of fore 
wing 5.0 mm. Head chestnut brown, each 
antenna chestnut brown, blending into yel- 
low at apex of flagellum; compound eyes 
light red-brown, extremely large. Thorax 
chestnut brown, with yellow areas along 
anterior lateral margins of mesoscutum, on 
prescuta, at wing bases, at apex of scutellum, 
and on anteromedian.and dorsolateral areas 
of metanotum; all legs yellow, except coxae 
