Observations on the chromosomes of four South American Libellulidae (Anisoptera)

The meiotic sequence and the mitotic complements were examined in the males of Tauriphila risi Martin, Perithemis icteroptera (Sel.), P. mooma Kirby and Miathyria marcella (Sel.) (n=13, 2n=25). An m-pair is lacking in P. icteroptera only. The chromosome morphology at diakinesis (ring-shaped bivalents) and prophase II is discussed. Precocious disjunction is reported in P. mooma and T. risi. Variation in size of the m-bivalent in P. mooma and M. marcella could reflect a polymorphic and polytypic situation, respectively.