. Bulletin. Natural history; Natural history. May, 1953 Burks: The Mayflies of Illinois 19 branch of M. Actually, as good a case can be made for considering this vein a branch of Rg as of M. It is not clearly joined to either, but sometimes appears to arise nearer the stem of R than of M. The poorly de- veloped axillary sclerites of the mayfly wing give no conclusive evidence either way. Such being the case, I have decided to follow Traver's system, in which this vein is con- sidered to be a branch of Rj, as her system was used consistently in The Biology of Mayflies (Traver 1935a). This work
. Bulletin. Natural history; Natural history. May, 1953 Burks: The Mayflies of Illinois 19 branch of M. Actually, as good a case can be made for considering this vein a branch of Rg as of M. It is not clearly joined to either, but sometimes appears to arise nearer the stem of R than of M. The poorly de- veloped axillary sclerites of the mayfly wing give no conclusive evidence either way. Such being the case, I have decided to follow Traver's system, in which this vein is con- sidered to be a branch of Rj, as her system was used consistently in The Biology of Mayflies (Traver 1935a). This work has been, and is most likely to continue for many years to be, the standard reference work on North American mayflies. It should further be noted that the veins called Mj and M., by Traver have been called Cu^ and Cu,,'by Ulmer, MP by Till- yard, and branches of vein 7 by Eaton. The veins Cu^ and Cu„ of Traver's system cor- respond to 1st and 2nd anal veins of Ulmer's, Cuj and Cu^ of Tillyard's, and veins 8 and 9 of Eaton's. In mayfly literature, it is frequently stated. opical 'angle genital forceps .forceps base Fig. 8.—Dorsal aspect of generalized mayfly nymph, showing structures used in classification. Fig. 9.—Generalized mayfly wings, showing principal veins and areas used in classification. Fig. 10.—Generalized mayfly male genitalia, showing structures used in classification: a, discal spines; b, subapical spines; c, apical spines; d, apicomesal spines; e, lateral spines; f, basal spines; g, mesal 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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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
