Náttúrufræðingurinn - 1976, Síða 112

212
NÁTTÚRUFRÆÐINGURINN
lengri tíma, og hafa þær venjulega 10—15 hamskipti í uppvextinum.
Bæði fullorðin dýr og nýmfur lifa á ránum, og þykja nýmfurnar
hinir mestu ógnvaldar öðrum dýrum í tjörnunum, en geta gert tals-
vert gagn með því að halda moskítóflugum í skefjum.
SU M M ARY
The dragonfly Hemianax ephippiger (Burm.) (Odonada), an unexpected
guest in lceland.
The dragonfly Hcmianax ephippiger (Burm.), native to the desert districts
o£ Africa and soutliern Asia, is known to migrate from its normal home range
and has been discovered in Europe as far north as to the British Isles.
Norling (1967) reported two specimens found in Iceland (in late September
1941 and on October llth 1964). Mikkola (1968) examined weather maps from
the days before the latter discovery and showed, that the meteorological situation
in Europe was suitable for passive anemochorous dispersal from the eastern
part of the Mediterranean via Scandinavia to Iceland.
In 1971 (October 29th and November 5th) two more specimens were found
in Iceland (Westman Islands), the first specimen probably found alive, but
the latter probably dead, so they most likely arrived to Iceland simultaneously.
Now the weather situation highly favoured an anemochorcus dispersal from the
western Mediterranean over tlie Atlantic to Iceland, and tliat holds for the days
October 26th to 28th. This means that there hardly remains any doubt, that
the species is capable of reaching Iceland on its own wings.
HEIHILDARIT
Chinery, M., 1973: A Field Guide to the Insects of Britain and Northern Europe.
Friðriksson, Á., 1941: Glermær lieimsækir ísland. Náttúrufræðingurinn, II:
180-181.
Lindroth, C.H., Andersson, H., Böðvarsson, H., Richter, S.H., 1973: Surtsey,
Iceland. The Development o£ a New Fauna, 1963—1970. Terrestrial In-
vertebrates. Entomologica Scandinavica, Suppl. 5: 102—103.
Miltkola, K., 1968: Hemianax epliippiger (Burm.) (Odonata) carried to Iceland
frorn the Eastern Mediterranean by an aircurrent? Opusc. Ent., 33:
111-113.
Norling, IJ., 1967: Hemianax ephippiger (Burm.) found in Iceland (Odonata).
Opusc. Ent., 32: 99-100.