Observations on Libellula fulva Müll. in the central Netherlands (Anisoptera: Libellulidae)

L. fulva is a rare and very local species in the Netherlands. May 20, 1978, 2 9 were taken near the village of Breukelen (Utrecht Prov.). The subsequent records were made, all in 1978, in the surroundings of the Kortenhoefse Plassen (i.e. the "Oppad”), in Bussum (the estate ”Beek”; both Noord-Holland Prov.) and at the Loosdrechtse Plassen ("Kromme Rade”, the border area between the Utrecht and Noord-Holland Prov.). The species has been seen on wings for the last time on July 13. it is amazing that in spite of very thorough surveys in the area during the preceding five years. L. futva has not been encountered earlier in the region. The causes of its sudden massive occurrence in 1978 remain a puzzle.