May, 1953 
somewhat lighter; wings hyaline, all veins 
only very slightly darker than membrane. 
Caudal filaments white throughout. Geni- 
talia, fig. 124: penis lobes with a pair of 
prominent, lateral tubercles, second forceps 
segment slightly bowed, and third forceps 
segment as broad as long. 
NympH.—Head, thorax, and legs conspic- 
uously hairy; maxillary palp present, but 
reduced; fore femur not toothed on anterior 
margin, but bearing a few spicules; ab- 
dominal tergites with a double row of sub- 
mesal, papillate protuberances; caudal fila- 
ments bearing only short spines throughout 
their length. 
Known from Ontario and Quebec. 
8. Ephemerella serrata Morgan 
(1911: 109). 
Mave.—Length of body and of fore wing 
5-6 mm. Thorax yellow-brown, abdominal 
tergum red-brown, and abdominal venter 
yellow-brown, without transverse rows of 
black dots. Wings hyaline, tinged with 
brown at bases, and veins faintly shaded. 
Genitalia, fig. 128, with penis lobes fused 
almost to tips, and a lateral tubercle present 
on each penis lobe near tip; second forceps 
segment bowed toward apex; third forceps 
segment as broad as long. 
NympH.—Vertex of head roughened, but 
without distinct tubercles. Prothorax with 
a pair of small, submedian, dorsal tubercles 
near posterior margin; each tarsal claw 
with three or four denticles. Abdominal 
tergites with a double row of submedian, 
wartlike tubercles; caudal filaments bearing 
only short setae. 
Known from Maryland, Massachusetts, 
New York, North Carolina, Quebec, and 
West Virginia. 
Ephemerella serrata Morgan 
9. Ephemerella serratoides McDunnough 
Ephemerella serratoides McDunnough 
(1931b: 83; 1931d:207). 
Mate.—Length of body and of fore wing 
5-6 mm. Thorax yellow-brown, with dark 
brown shading; abdominal tergites  red- 
brown, with darker brown markings; ab- 
dominal sternites lighter in color than ter- 
gites, each sternite bearing an arcuate, trans- 
verse row of four black dots; wings hyaline, 
with veins faintly shaded. Genitalia, fig. 126, 
differ only slightly from those of serrata. 
Burks: THE MAyF Lies oF ILLINOIS 67 
NympH.—Head and thorax smooth, with- 
out tubercles or conspicuous hairs; fore 
femur bearing a few spicules on posterior 
margin; each tarsal claw with six or seven 
denticles. Abdominal tergites with a double 
row of small, submedian, wartlike pro- 
tuberances; caudal filaments with only short 
setae. 
Known from Maryland, North Carolina, 
Quebec, and West Virginia. 
10. Ephemerella deficiens Morgan 
Ephemerella deficiens Morgan (1911:111). 
Ephemerella atrescens McDunnough 
(1925¢:43). 
Mave.—Length of body and of fore wing 
5-6 mm. Head and body very dark brown, 
with abdominal sternites uniformly tan. 
Wings hyaline, with brown staining at wing 
bases; veins faintly darker than wing mem- 
brane. Genitalia, fig. 133: penis lobes fused 
only two-thirds of the way to tips, and 
lateral tubercles present on each penis lobe 
near apex; second forceps segment is rela- 
tively straight. 
NympH.—Head and thorax smooth, with- 
out tubercles; maxillary palp entirely want- 
ing, fig. 169; each tarsal claw with eight or 
nine denticles. Abdominal tergites lacking 
mid-dorsal tubercles; caudal filaments bear- 
ing only short setae. 
Known from Georgia, Massachusetts, 
Michigan, New Brunswick, New Hamp- 
shire, New York, North Carolina, Nova 
Scotia, Ontario, Quebec, and West Virginia. 
INVARIA Group 
11. Ephemerella needhami McDunnough 
Ephemerella excrucians Needham (1905: 47), 
not Walsh. Misidentification. 
Ephemerella needhami McDunnough 
(1925b:171). New name. 
Matce.—Length of body and of fore wing 
6-8 mm. Head, thorax, and abdominal 
tergum dark red-brown to almost black; 
abdominal venter mostly light red-brown. 
Head red-brown, face below ocelli yellow; 
in life, each eye red-tan in upper portion, 
yellow in lower portion; antennal scape 
yellow, pedicel and flagellum brown. Tho- 
rax dark red-brown to almost black, with 
yellow spot on sternum between each pair 
of coxae; fore leg smoky brown, middle and 
hind legs yellow, with vague brown shading 
