. Bulletin. Natural history; Natural history. May, 1953 Burks: The Mayflies of Illinois 57 shown by unbroken lines. These stout spines borne by the penis lobes occur in three posi- tions on the lobes: apical, near or at the apex near the meson; lateral, at or near the outer lateral margin of each penis lobe a short distance from the apex; and basal, approximately midway between base and apex of the penis lobe; see fig. 10. The following keys to the genus Epheme- rella do not include the species consimiUs Walsh, described in 1862, from Rock Island, Illinois. No authentic Walsh material of this
. Bulletin. Natural history; Natural history. May, 1953 Burks: The Mayflies of Illinois 57 shown by unbroken lines. These stout spines borne by the penis lobes occur in three posi- tions on the lobes: apical, near or at the apex near the meson; lateral, at or near the outer lateral margin of each penis lobe a short distance from the apex; and basal, approximately midway between base and apex of the penis lobe; see fig. 10. The following keys to the genus Epheme- rella do not include the species consimiUs Walsh, described in 1862, from Rock Island, Illinois. No authentic Walsh material of this species is knovyn to exist, and the species cannot be identified from the description alone. Extensive collecting in and around Rock Island has failed to turn up any speci-. SORDIDA ATTENUATA. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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