DIPTERA

E.C.M. Haes

Updated by K.N.A. Alexander and hoverflies by L.A.C. Truscott

Historically there has been no major recorder of Diptera in Cornwall to match the work of G.M. Spooner with aculeate Hymenoptera. However his part contemporary, the Rev. A. Thornley of Carbis Bay, amongst a few others, added important records of rarer species during the 1920s and 1930s. In the post-1980 period important finds have been contributed especially by K.N.A. Alexander and as a result of a survey by English Nature under D. Sheppard on the Lizard National Nature Reserve. The Dipterists Forum have also held three of their summer field meetings in Cornwall, although all of the resulting data has not been made available locally. Thanks to the handbook by A.E. Stubbs (Stubbs & Falk, 2002) a number of recorders in Cornwall have made special efforts to record hoverflies over the last ten years, especially in east Cornwall (e.g. by L.A.C. Truscott). A most notable post-1980 discovery was Pocota personata (Harris) by B.E. Jackson in 1990. In addition several important post-1980 records of flies have been made by entomologists working on other groups. A notable example was the discovery by the hymenopterist M. Edwards of a RDB1 species the tachinid Cyclindromyia brassicaria (Fabricius) at Loe Bar in 1990. In general, however, the Diptera remain an under-worked group in Cornwall and the Isles of Scilly. From general observation, Cornwall could be an exceptionally good area for coastal, marshland or stream-side Crane-flies, and the Tipulidae are probably worth special investigation. However, of necessity the species selected for this entry cover primarily those included in the Joint Nature Conservation Committee’s national reviews of Diptera (Falk, 1991; Falk & Chandler, 2005; Falk & Crossley, 2005). More up-to-date statuses are available for Tephritidae (Clemons, 1996).

Because so many species of flies need to be identified by experienced and usually specialist recorders, only species accepted as confirmed by the organisers of the several National Recording Schemes - e.g. of Crane Flies (Tipulidae) or Hoverflies (Syrphidae) - are listed in this chapter. No RDB Robberflies, Bee-flies, or Stratiomyids have been recorded in Cornwall since 1980. The records of the upland species Platycheirus melanopsis Loew (RDB3) and Tipula grisescens (Zetterstedt) (Notable) from The Lizard (in 1980 and 1981 respectively) are probably the result of misidentification. Many species have not been recorded since 1980, e.g. the RDB hoverflies Brachyopa bicolor (Fallén), Chrysotoxum octomaculatum Curtis, Chrysototum vernale Loew and Eristalis cryptarum (Fabricius). The following Notable hoverflies were also once present in Cornwall but have not been recorded since 1980: Cheilosa mutabilis (Fallen), Cheilosa soror (Zetterstedt), Criorhina asilica (Fallén), Eumerus ornata Meigen, Mallota cimbiciformis (Fallén), Paragus tibialis (Fallén), Platycheirus sticticus (Meigen) and Volucella inanis (Linnaeus). The Notable Tephritid Paroxyna producta (Loew) has only been recorded in Cornwall before 1960. The RDB Crane-fly Erioptera meigeni (Zetterstedt) has not been recorded for the Isles of Scilly since about 1904 and Gonomyia sexguttata (Dale) not recorded in Cornwall since the record at St. Merryn in 1912 (one of only two known sites in Britain for this RDB1 species and now a golfcourse); the notable Crane-fly Tasiocera laminata Freeman, not recorded in Cornwall since the 1970s, is likely to be refound with careful search.

The classification of RDB and Nationally Scarce (= Notable) species is taken from Falk (1991); Falk did not separate the Diptera into Na and Nb, so species are listed as Notable if they occur within the range of 16 to 100 10km squares in Britain. Other useful reference works are the provisional atlases on Tipulinae (Stubbs, 1992) and the larger Brachycera (Drake, 1990). The fly groups are organised alphabetically in the following accounts.

1. ASILIDAE (Robberflies)

Asilus crabroniformis Hornet Robberfly

2. BOMBYLIIDAE (Bee-flies)

Bombylius canescens Bee Fly

3. CONOPIDAE

Myopa extricata Wasp Fly

4. DOLICHOPODIDAE (Dollies)

Acropsilus niger

Acropsilus mitis

Chrysotus verralli

Syntormon mikii

5. EMPIDIDAE, ATELESTIDAE (Dance Flies)

Atelestus dissonans

6. MYCETOPHILIDAE & KEROPLATIDAE (Fungus Gnats)

Monocentrota favonii

Neoplatyura biumbrata

7. PIPUNCULIDAE (Big-headed Flies)

Cephalosphaera germanica

Eudorylas zermattensis

8. STRATIOMYIDAE

Beris clavipes Soldier Fly

Beris fuscipes Soldier Fly

Oxycera morrisii

9. SYRPHIDAE (Hoverflies)

Platycheirus discimanus

Platycheirus immarginatus

Platycheirus perpallidus

Xanthandrus comtus

Chrysotoxum elegans

Didea fasciata

Epistrophe diaphana

Eupeodes latilunulatus

Meligramma guttatum

Parasyrphus nigritarsis

Brachyopa insensilis

Callicera aurata

Orthonevra brevicornis

Orthonevra geniculata

Sphegina verecunda

Eumerus sabulonum

Pipizella virens

Volucella inflata

Volucella zonaria

Criorhina ranunculi

Pocota personata

Xylota florum

Microdon myrmicae

10. TABANIDAE (Horse-flies and Clegs)

Atylotus fulvus

Tabanus cordiger

11. TEPHRITIDAE (Fruit Flies)

Acanthiophilus helianthi

Campiglossa producta

Chetostoma curvinerve

Cryptaciura rotundiventris

Myopites eximia

Oxyna flavipennis

Stemonocera cornuta

Terellia vectensis

Urophora spoliata

12. TIPULIDAE & LIMONIIDAE (Crane-flies)

Atypophthalmus inusta

Ctenophora pectinicornis

Dicranomyia goritiensis

Dicranomyia ventralis

Diogma glabrata

Gonomyia conoviensis

Lipsothrix nervosa

Phylidorea abdominalis

Pilaria fuscipennis

Tanyptera nigricornis

Tipula yerburyi