144 IttrNors NarurAL History SuRVEY BULLETIN 
7. Cloeon vicinum (Hagen) 
Cloe vicina Hagen (1861:56). 
Mare—Length of body 4 mm., of fore 
wing 4-5 mm. Thorax almost completely 
light yellow-brown, only slightly darker on 
mesoscutum; wings hyaline and in stigmatic 
area of each wing five or six crossveins 
which do not quite reach subcostal vein; 
legs white, with each fore coxa and base 
of fore femur stained with tan. Abdominal 
segments 2-6 white, without red or brown 
markings; apical tergites dull brown; apical 
sternites very light tan; genital forceps 
white, basal segment of each bearing a very 
small, mesoapical projection; caudal fila- 
ments white. 
Known from the District of Columbia, 
New York, and West Virginia. 
8. Cloeon simplex McDunnough 
Cloeon simplex McDunnough (1925b:185). 
Mate.—Length of body 4.5-5.5 mm., of 
fore wing 5-6 mm. Head brown, scape and 
pedicel of each antenna yellow, flagellum 
brown. Thoracic notum brown, with pos- 
terior margins of pronotum and mesoscutum 
and entire mesoscutellum white; pleura 
white, with vague, tan shading; prosternum 
white; meso- and metasternum brown, with 
white markings; wings hyaline; legs white. 
Abdominal segments 1-6 translucent white, 
with longitudinal, black spiracular lines; 
apical tergites yellow-brown, sternites white, 
opaque; genital forceps and caudal filaments 
white. 
FremMALe.—Length of body 5-6 mm., of 
fore wing 6-7 mm. Head and thorax yellow 
or light tan, sometimes tinged with green; 
abdomen yellow, with extensive, black tra- 
cheal and spiracular markings; legs white, 
wings hyaline, both sometimes with green 
stain. 
Known from Illinois, Indiana, Ontario, 
Quebec, and Wisconsin. 
Illinois Records——RicHMoND: June 13, 
1938, B. D. Burks, 1¢. Rosecrans: Des 
Plaines River, June 1421, 1938, B. D. 
Burks, 14,39,5 N. Sprinc Grove: June 
9, 1938, Mohr & Burks, 1 2. 
AMETROPIDAE 
This family as treated here includes some 
of the genera that were placed in the fami- 
Vol. 26, Art. IT 
lies Ametropodidae and Ecdyonuridae in 
Ulmer’s classification (1933), and repre- 
sents a combination of the subfamilies Ame- 
tropinae and Metretopinae of Traver’s clas- 
sification (1935a:429, 433). Lestage (1938: 
180) has divided these genera among three 
families, Ametropodidae, Metretopodidae, 
and Siphloplectonidae. 
The Ametropidae contain forms which are 
interstitial between the typical heptageniids 
and the typical baetids. The wing venation 
is quite similar to, or identical with, that of 
the Heptageniidae, but the hind tarsus in 
all ametropid genera has only four clearly 
differentiated segments. The nymphs re- 
semble either the heptageniid or baetid form, 
but the tarsal claws of the middle and hind 
legs are slender (at least six times as long 
as greatest width) and usually longer than 
their respective tibiae, figs. 25, 301, 302, 312. 
In the male ametropid adults, the fore 
tarsus is from two and one-half to nearly 
five times as long as the fore tibia, the first 
fore tarsal segment varies from three- 
fourths to one and one-half times as long as 
the second segment; the compound eyes are 
almost or quite contiguous on the meson, 
each eye is obscurely divided into an upper 
area of larger facets and a lower area of 
slightly smaller facets, and the living insect 
often has a faint color band crossing the 
eye at the boundary line between the two 
areas of facets in the eye. In both sexes, 
the cubital intercalaries, fig. 308, consist of 
two or, more often, four straight veins 
which are detached at the bases; the hind 
wing always has a broadly angulate costal 
projection; and vein M of the hind wing is 
forked near the wing base, or, farther dis- — 
tad, near the middle of the wing. In both — 
sexes of all members of this family, the 
abdomen is markedly long and slender, with — 
the apical segments more slender and elon- — 
gate than are the basal segments. There may 
be either two or three well-developed caudal 
filaments. 
In the nymphs, which are quite hetero- 
geneous, the head is flattened laterally or — 
dorsoventrally and the eyes are directed an- — 
teriorly, dorsally, or laterally. The fore 
tarsal claw is single, slender, and long in 
Pseudiron, Ametropus, and Metreturus, but 
bifid in Siphloplecton, fig. 303, and Metre- — 
topus; the claws of the middle and hind 
legs are longer than their respective tibiae, © 
figs. 301, 302. In the nymphs of most gen- 
