A Revisionary Study of the Genus Acanthagrion (Odonata: Zygoptera)
Justin W. Leonard
Of unusual occurrence is the publication oI a thesis 40 years after its completion and acceptance in partial tultilln~cnt of the requirements for the Doctor of Philosophy degree, ant1 also nIter the death of the author. Such thesis is herewith published in the Miscellnneous Publications of the Museum of Zoology, as a memorial number for Dr. Justin W. Leonard.
The greater part of the study reported here was carried on during the period 1931-34 while Dr. Leonard was a graduate student at the University of Michigan. Since that time, the varied demands of his professional duties, and the difIiculties in obtaining funds for the printing, resulted in repeated delays or publication. A few years ago, Dr. B. E. Montgomery and Dr. Leonard began to revise the original mCmuscript and made a few minor changes in the Introduction and preliminary discussion concerning the genus Acantha,qrzon. These have been incorporated in this published version. The hopeful waiting ior the publication of this work has apparently been responsible for the delay in describing new species by other authors. Since the completion of the thesis, only six new species and two new subspecies have been described. These arc listed herewith in
an Appendix. Leonora K. Gloyd