Norellia spinipes
A pale coloured species with strongly spined front legs and marked wings (a dark cloud over both the anterior and posterior cross-veins and a dark spot near the apex of the wing). The thorax is mainly dull with four dark longitudinal stripes, but is narrowly shining along the dorsocentrals rows. Abdomen shining with a dark central stripe. Head mainly yellow, but with triangular black patches on the occiput either side of a broad, pale, central line. Ocellar triangle dark. Antennae yellow. Legs entirely pale. Wing length: ♂ 5.3 - 6.1 - 6.7 mm (16); ♀ 6.4 - 6.7 - 7.3 mm (5).
It is associated with daffodils (Narcissus). The larvae mine the leaves and pupate at the base of the plant and sometimes damage the bulbs (Smith, 1989[1]). Most records are for the Spring (April to June) when adults are usually found on daffodil leaves, but there are also October records which seem to always relate to females. No specimens earlier than 1965 have come to light, although it is not uncommon at some localities within its limited range. This suggests it is a recent colonist and was probably introduced from the continent in imported bulbs. De Jong (1985)[2] discusses the past confusion between this species and N. tipularia and concludes that N. spinipes has only been recorded with certainty from Britain, France and the Netherlands.
References
Norellia spinipes and Norellisoma spinimanum are frequently confused. They are of similar size and general colouring and the most obvious feature of both are the strongly spined, mantis-like front legs. The feature used in the key: a single row of strong spines on the tibia of Norellia, two rows in Norellisoma; is not actually easy to see, especially if the legs are folded. The inner row of strong spines in Norellisoms is often hidden by the leg itself in both specimens and photos. The wing markings of Norellia are also quite subtle and not all that obvious. However, Norellia only has two pairs of strong dorsocentral bristles on the thoracic dorsum whereas N. spinimanum has five pairs (the two smaller Norellisoma species have three pairs). Since most photos are taken at least somewhat from above, this difference is usually visible and therefore very useful in separating photos of these two species.
This rather distinctive species was first recorded in 1965 (Chandler and Stubbs, 1969[1]; Chandler, 1970[2]) and has been found mainly in deciduous woodland or in gardens in Surrey, Kent, Sussex, Bucks, Berks, Herts, Cambs., Hunts. and Middlesex (Allen, 1970[3]; Godfrey, 1989[4]; Smith, 1996[5]; Smith & Vardy, 1988[6]).
World distribution: Palaearctic: Europe: Carpathian Mountains, Belgium, Czech Republic, France, Germany, Greece, Hungary, Italy, Netherlands, Poland, Slovakia, Spain, Sweden, Switzerland; North Africa: Algeria; Russia: Southern European regions.
References
- , 1969. A species of Norellia R.-D. (Dipt., Scatophagidae) new to Britain. Proceedings of the British Entomological and Natural History Society, 2, pp.120-124.
- , 1970. A supplementary note on Norellia R.-D. (Dipt., Scatophagidae). Proceedings of the British Entomological and Natural History Society, 3, p.12.
- , 1970. Further notable Diptera from Windsor Forest. Entomologist's Record And Journal Of Variation, 95, pp.24-28.
- , 1989. Norellia spinipes in London. British Journal of Entomology and Natural History, 2, p.63.
- , 1996. A further Middlesex locality for Norellia soinipes (Mg.) (Dipt., Scathophagidae). Entomologist's monthly Magazine, 132, p.54.
- , 1988. A further British record of Norellia spinipes (Meigen) (Dipt., Scathophagidae) from daffodils in Middlesex. Entomologist's monthly Magazine, 124, p.242.