. Bulletin - New York State Museum. Science. 22 NEW YORK STATE MUSEUM three forked veins are followed by three tjipically simple veins, the first, second and third anal veins, which occuipy the smaller area of the hind angle of the wing. There is mu'ch variability in this region in the different genera, and it is highly important that these three veins 'be certainly recognized; to do this it is only necessary to count off the three longitudinal veins of the cubitus—the two branches (Cic-^ and CUo) and the bisector of the cuJbital fork—^back of the media, and these three will be the three best
. Bulletin - New York State Museum. Science. 22 NEW YORK STATE MUSEUM three forked veins are followed by three tjipically simple veins, the first, second and third anal veins, which occuipy the smaller area of the hind angle of the wing. There is mu'ch variability in this region in the different genera, and it is highly important that these three veins 'be certainly recognized; to do this it is only necessary to count off the three longitudinal veins of the cubitus—the two branches (Cic-^ and CUo) and the bisector of the cuJbital fork—^back of the media, and these three will be the three best developed veins remaining. In the keys the short, incon- stant interpolated longitudinal veins are called intercalaries, and that whether the^^ become attached to principal veins or branches or remain independent; and the irregular veins about the margin. Fig'. 3 Venation of the fore wing- of E p h e m ei* a of the wing are called veinlets. The length of the media is meas- ured on vein M.^. The fore wing is meant in the key except where the hind wing is specified. shows the unilateral forking of the cubital vein and the divergence of the culbital and first anal veins at base, characteristic of the subfamily Ephemerinae. KEY TO THE GENERA OP MAYFLIES OF NORTH AMERICA Jmagos a The cubital and first anal veins strongly divergent at the base (). Venation never greatly reduced Ephemerinae 1) The fork of the median vein very deep, almost reaching the wing base; two long simple intercalaries between the first and second anal veins. In the hind wing the vein R^ separates from vein Ri close beside and therefore is little longer than the next branch of the radial sector C a m p s u r u s 1)1) The median vein forked for not more than three fourths of its length; in the hind wing the vein Rg arises much in advance of other branches of the sector, being much longer than any of them. Please note that these images are extracted from scanned page images that may have been digita
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectscience, bookyear1887
