. Fresh-water biology. Freshwater biology. 9i8 FRESH-WATER BIOLOGY KEY TO NORTH AMERICAN MAYFLIES Imagos 1 (13) The cubital and first anal veins strongly divergent at the base (Fig. 1387). Venation never greatly reduced 2 2 (3) The posterior fork of the median vein very deep, almost reaching the wing base; two long simple intercalaries between the first and second anal veins Cantpsurus. 3 (2) The posterior fork of the median vein (M3-M4) forked for not more than three-fourths of its length 4. ; â *⢠Fig. 1387. The wings of Ephemera. (Drawn by Dr. Anna H. Morgan.) 4 (s) Between the first and s
. Fresh-water biology. Freshwater biology. 9i8 FRESH-WATER BIOLOGY KEY TO NORTH AMERICAN MAYFLIES Imagos 1 (13) The cubital and first anal veins strongly divergent at the base (Fig. 1387). Venation never greatly reduced 2 2 (3) The posterior fork of the median vein very deep, almost reaching the wing base; two long simple intercalaries between the first and second anal veins Cantpsurus. 3 (2) The posterior fork of the median vein (M3-M4) forked for not more than three-fourths of its length 4. ; â *⢠Fig. 1387. The wings of Ephemera. (Drawn by Dr. Anna H. Morgan.) 4 (s) Between the first and second anal veins is a bunch of three or four long straight intercalaries, conjoined basally before their attach- ment to the principal veins; the second anal vein nearly straight and unbranched. Polymitarcys. 5 (4} Between the first and second anal veins are only shorter, sinuate, and sometimes forking intercalaries, attached directly to the first anal; the second anal vein sinuate and often branched (Fig. 1387) 6 6 (7) The posterior fork of the median vein forked two-thirds to three-fourths its length; vein Cu2 not more strongly bent at base than the first anal Euthyplocia. 7 (6) This fork of the median vein occupying not more than half its length; vein Cu2 more strongly bent at base than is the first anal (Fig. 1387) 8 8 (12) The third anal vein simple, but attached to the hind margin by a number of cross veins; in the narrow posterior fork of the median vein there are one or more cross veins before the origin of the intercalary; male forceps four-jointed 9 9 (10, 11) Caudal setae three in both male and female; fore tarsus of female imago three-fourths as long as the tibia. . Ephemera. 10 (9, 11) Caudal setae two in the male and three in the female; fore tarsus of the female two-thirds as long as the tibia. Pentagenia. 11 (9,10) Caudal setae two in male and female; fore tarsus of female as long as the tibia Please note that these images are extracted from scann
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
