. Bulletin. Natural history; Natural history. May, 1953 Burks: The Mayflies of Illinois 63 with a pair of dark, lateral streaks only 6. frisoni {INVARIA Group) 14. Abdominal tergites with a double row of erect, conspicuous tubercles 11. needhami Abdominal tergites either entirely without paired dorsal tubercles, or with small to minute ones, figs. 165, 166, 173 ...15 15. Legs markedly long and slender, spider- like 13. septentrionalis Legs not markedly long and slender . 16 19. abdominal tergites 5 and 6 mostly brown 18 Dorsum ot mesothorax freckled with pale dots in addition to the usual 16 r
. Bulletin. Natural history; Natural history. May, 1953 Burks: The Mayflies of Illinois 63 with a pair of dark, lateral streaks only 6. frisoni {INVARIA Group) 14. Abdominal tergites with a double row of erect, conspicuous tubercles 11. needhami Abdominal tergites either entirely without paired dorsal tubercles, or with small to minute ones, figs. 165, 166, 173 ...15 15. Legs markedly long and slender, spider- like 13. septentrionalis Legs not markedly long and slender . 16 19. abdominal tergites 5 and 6 mostly brown 18 Dorsum ot mesothorax freckled with pale dots in addition to the usual 16 rela- tively large, pale spots . .17. dorothea Dorsum of mesothorax uniform deep brown, with relatively large, pale spots only 16. excrucians Lateral spines of apical abdominal ter- gites well developed, those of eighth segment twice as long as wide at base; hind leg with tibia longer than femur 12. aurivillii. Fig. 158.—EphemercUa luliilenta, dorsal tubercles of basal abdominal segments of mature nymph, lateral aspect. Fig. 159.—Ephemerella coxalis, dorsal tubercles of basal abdominal segments of mature nymph, lateral aspect. Fig. 160.—Ephemerella cornuta, fore femur of mature nymph. Fig. 161.—Ephcmeiflla needhami, fore femur of mature nymph. Fig. 162.—Ephemerella simplex, right side of abdomen of mature nymph, dorsal aspect. Fig. 163.—Ephemerella lita, right side of abdomen of mature nymph, dorsal aspect. Fig. 164.—Ephemerella temporalis, right side of abdomen of mature nymph, dorsal aspect. Fig. 165.—Ephemerella subvaria, right side of abdomen of mature nymph, dorsal aspect. Fig. 166.—Ephemerella rotunda, right side of abdomen of mature nymph, dorsal aspect. 16. 17. Paired dorsal tubercles of abdomen en- tirely lacking 17 Abdomen with at least rudimentary paired dorsal tubercles 19 Lateral margin of eighth abdominal tergite sinuate, fig. 173; abdominal tergites 5 and 6 almost completely white 14. argo Posterior two-thirds of each lateral mar- gin of eighth a
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
