Chrysops caecutiens

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Chrysops caecutiens
Tabanidae - Chrysops caecutiens.JPG
Female of Chrysops caecutiens
Male on Leucanthemum vulgare
Scientific classification edit
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Tabanidae
Subfamily: Chrysopsinae
Tribe: Chrysopsini
Genus: Chrysops
C. caecutiens
Binomial name
Chrysops caecutiens
  • Tabanus caecutiens Linnaeus, 1758
  • Tabanus lugubris Linnaeus, 1761
  • Tabanus maritimus Scopoli, 1763
  • Tabanus coecutiens Müller, 1775
  • Tabanus nubilosus Harris, 1776
  • Chrysops crudelis Wiedemann, 1828
  • Chrysops ludens Loew, 1858
  • Chrysops caecutiens f. meridionalis Strobl, 1906
  • Chrysops hermanni Kröber, 1920
  • Chrysops caecutiens var. trifenestratus Kröber, 1920
  • Chrysops caecutiens f. niger Goffe, 1931
  • Chrysops caecutiens f. nigrescens Goffe, 1931
  • Chrysops caecutiens f. obsolescens Goffe, 1931
  • Chrysops caecutiens f. obsoletus Goffe, 1931
  • Chrysops caecutiens f. fulvus Goffe, 1931
  • Chrysops caecutiens f. clarus Goffe, 1931
  • Chrysops caecutiens f. hyalinatus Goffe, 1931

Chrysops caecutiens, common name splayed deer fly, is a species of horse fly belonging to the family Tabanidae.[1] It is also known by the colloquial name Scotch Cleg.[2][3][4][5]


Chrysops caecutiens reaches a length of about 8.5–10 millimetres (0.33–0.39 in).[6] The mesonotum and the scutellum are glossy black with yellow-brown hairs. The compound eyes have red and green reflections, with dark spots. The transparent wings have dark brown patches, located at the top and at the centre of each wing. The abdomen shows distinct black inverted-V marking (hence the common name of "splayed" deer fly). The legs are black, included the tibiae on the middle pair of legs. They are active from May to September.[6]

Chrysops caecutiens


The larvae of the splayed deer fly feed upon algae and organic matter in damp muddy soils.[6] The adult female flies feed on mammalian blood (including on roe deer),[7] in order for their eggs to mature properly. When they bite, they inject saliva with an anti-coagulating agent that prevent the blood clotting. The structure of the ommatidia in the midregion of the eyes of the females may use high polarization to assist in host-finding.[8] Adult males and females feed also on nectar and pollen of flowers (mainly Leucanthemum vulgare).[6][7]


This species is present in most of Europe, the eastern Palearctic realm, and the Near East.[9]


These horseflies preferably live in shaded marshlands and in damp woodlands.[6]


  1. ^ Biolib
  2. ^ Verrall, G. H. (1909). Stratiomyidae and succeeding families of the Diptera Brachycera of Great Britain British flies. Vol. 5. London: Gurney and Jackson. pp. 780, 34 p., 407 fig. Retrieved 19 October 2022.
  3. ^ Stubbs, Alan E.; Drake, Martin (2001). British Soldierflies and their allies: A Field Guide to the Larger British Brachycera (Print). London: British Entomological and Natural History Society. pp. 528 pages. ISBN 1-899935-04-5.
  4. ^ Moucha, J. (1976). "Horse-flies (Diptera: Tabanidae) of the World. Synoptic Catalogue" (PDF). Acta Entomologica Musei Nationalis Pragae Supplements. 7: 1–320. Retrieved 11 September 2022.
  5. ^ Chvála, Milan; Lyneborg, Leif; Moucha, Josef (1972). The Horse Flies of Europe (Diptera, Tabanidae). Copenhagen: Entomological Society of Copenhagen. pp. 598pp, 164figs. ISBN 978-09-00-84857-5.
  6. ^ a b c d e J.K. Lindsey Commanster
  7. ^ a b Global species
  8. ^ Hansjörg Wunderer, Ulrich Smola Functional morphology of the retina of Chrysops caecutiens
  9. ^ "Chrysops (Chrysops) caecutiens (Linnaeus, 1758)". 2.5. Fauna Europaea. July 23, 2012. Archived from the original on January 25, 2016. Retrieved February 9, 2013.