Taxonomy
Chrysogaster virescens
Distribution
Species Biology
Preferred environment
Forest/wetland; fen carr plus small open areas with flushes and streams in deciduous forest. Most Irish records of this insect are from alongside streams flowing through poorly-drained, scrub-invaded pasture. Other records are from beside streams in Quercus woods, or from scrub and pasture beside lakes. C. virescens is a rather enigmatic species in that only isolated specimens are usually met with.
Adult habitat & habits
Alnus/Salix carr and poorly-drained scrub, streamsides in woodland; settles on foliage of bushes and trees; adults descend to drink from stream margins, in hot weather.
Flight period
End April/mid July. Larva: undescribed.
Flowers visited
White umbellifers, Filipendula, Ilex, Iris, Ranunculus.
Irish reference specimens
In the collections of NMI and UM
Determination
See Key provided in StN Keys volume. Until recently this species has been confused with the very similar C. rondanii Maibach & Goeldlin. The male terminalia are figured by Maibach et al (1994a) and Maibach and Goeldlin (1995). The adult insect is illustrated in colour by Bartsch et al (2009b) and Torp (1994).
Distribution
World distribution(GBIF)
Southern Finland, Ireland, Britain and the Atlantic seaboard of Europe from Denmark to the Pyrenees and northern Spain. Also in Switzerland, in central Europe. It is endemic to Europe and probably has a more restricted world range than any other syrphid known in Ireland - it is archetypally a species of Atlantic parts of Europe, hardly recorded away from the Atlantic zone.
Irish distribution
Given as occurring in Ireland in Coe (1953). C. virescens is not infrequent in Ireland, especially in the west.
Temporal change
Records submitted to Data Centre in 2025
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References
Publications
Speight, M. C. D. (2008) Database of Irish Syrphidae
(Diptera). Irish Wildlife Manuals, No. 36. National Parks and Wildlife Service.
Department of Environment, Heritage and Local Government, Dublin, Ireland.
Speight, M.C.D. (2014) Species accounts of European
Syrphidae (Diptera), 2014. Syrph the Net, the database of European Syrphidae,
vol. 78, 321 pp., Syrph the Net publications, Dublin.