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"A Nature Observer′s Scrapbook"

Flies - True, two winged flies of the order Diptera.

Page 2 - Dance flies, Soldier flies, Snipe flies, Gall flies and Horse flies.


Empis trigramma Empis trigramma

Dance-fly

Empis trigramma

Identifying an Empis genus can be relatively straightforward. The main features are the long curved slim proboscis, eyes that seem to occupy all of the head, a very thin neck, long legs and a small triangular wing cell at the tip of the wing.

But, within the Empis genus there are a large number of similar looking species. Many require microscope examination to identify to species and in others the differentiating features can be quite subtle.

They range in length from 7mm to 15mm and do not appear to exhibit much colour variation (many females exhibit the pale sided extended abdomen prior to egg laying as seen in the lower image), so I count myself fortunate to have had this one confirmed as Empis trigramma.

They get their common group name of 'Dance flies' from their habit of gathering in numbers in flight and 'dancing' in a cloud like gnats, usually over damp areas of ground.

They are, however, predatory insects and the long curved proboscis is used to spear other flies. It is common practice for the male to spear a fly and present it to a female as a 'pre-nuptial' gift prior to mating.

The larvae are also carnivorous and live in damp soil and leaf litter.



DateSighting
20.05.2005 Pair mating on Nettles by hawthorn hedge


Empis trigramma

Dance-fly

Empis livida

I am indebted to expert opinion for identifying this image as E. livida. Its small size, 9mm, can be guaged from the bramble flower that it is seen resting on. They are frequently seen around Hawthorn hedges in which the brambles occur.

They fly from April to July and will also be found on umbellifers such as Hogweed, supping nectar while waiting to satisfy their carnivorous tastes by spearing, with their long thin proboscis, any small fly that cares to join the nectar feast.

The larvae are also carnivorous and live in damp soil and leaf litter.



DateSighting
22.06.2003 On Bramble flowers.


Hilara Maura fly

Dance-fly

Hilara maura agg.

'When you have seen one black fly you have seen them all.'

Well, the males of the Hilara genera, of which there are some 60 UK species (hence the aggregate 'agg.' suffix) , are just a little bit different. Several of the species in the Emididae family employ a romantic twist to the mating ritual that involves the male presenting the female with a gift. This is usually a small fly. But the males of the Hilara spp. go one step further and gift wrap the present in silk that is exuded from the swollen glands on their front legs. In human terms, this is all part of a cunning ruse. While the female is pre-occupied with unwrapping her present, the male takes the opportunity to mate.

There are some 350 species of Empid flies and this genera is most easily recognised by its greatly swollen tarsi. They are common throughout the UK and can be seen swarming over water and marshy areas in the summer months. Length about 7mm.

Not a lot is known about their larvae.



DateSighting
15.05.2005 On Salix caprea by garden pond.
16.05.2009 On Salix caprea by garden pond.



Chloromyia formosa, female Chloromyia formosa, male a soldier fly larva

a 'Soldier fly'

Chloromyia formosa

Soldier flies get their common 'group' name from their bright colours - thought to be reminiscent of the soldiers uniforms of long ago. Most have broad flat abdomens that allow the abdomen colour to be seen even when the wings are closed and tightly folded.

At approximately 9mm long, these images have been identified as Chloromyia formosa. The upper image is of a female with its blue/green abdomen, the lower image is of the golden/bronze male. A similarly coloured but smaller species is the 5mm long Microchrysa polita.

Normally seen flying from May to August, both species are quite common in gardens. They breed in damp soil, compost and leaf litter and the larvae feed on decaying vegetable matter.

The 10mm larva shown here was found in soft rotting vegetation under a fruit bush but, since the larva was released where it was found and not reared to maturity, its true identity is not known. At best the image is representative of Stratiomyiid (Soldier fly) genera larvae. Generic features being the pointed anterior (head) section or capsule and the flattened bristly body.



DateSighting
07.06.2004 Larva found in rotting vegetation under fruit bush.
22.07.2007 Adult fly resting in full sun on the foliage of Salix caprea.
20.07.2008 Adult fly resting in full sun on the foliage of Salix caprea.



Soldier fly, Oxycera rara

a Soldier fly

Oxycera rara
..... also known as Oxycera pulchella, etc.

This colourful little Soldier fly is quite small, its head/body length only being about 7mm long. But, in its time, it has had seven different names as the taxonomists struggled to classify it properly. It is currently in the Stratiomyidae family grouping. There are several similar looking species. A much larger one is Stratiomys chameleon which is 14mm long.

This is not a very active fly. Its movement can best be described as sluggish and, between June and August, it seems to spend a lot of time sunbathing which makes it easier than most to get a good look at it. It favours damp habitats and breeds in moss and leaf litter. The larvae of others in the family are truly aquatic.

An interesting family feature, just about visible in the image, are the two rearwards facing spines that protrude from the scutellum (the yellow half-moon shaped area at the rear of the thorax).



DateSighting
27.07.2007 Found on low foliage near a garden pond.



Female Rhagio scolopacea Male Rhagio scolopacea

a Snipe Fly

Rhagio scolopacea


The wing venation of insects often gives a clue to their family relationships.These very clearly marked specimens, show the typical wing veining seen throughout the Snipe Fly family. The dark marks and shading on the wings then point to the specific species. There are several other Snipe Flies with unmarked wings that are not so easily identified!


The Snipe flies are predacious both as adults - catching smaller insects in mid air, and as larvae preying on underground insects and grubs.


The adult flies are usually found flying between May and August close to woodland or hedgerows.


The upper specimen is a female, as indicated by the eyes being set apart and the twin 'cerci' protruding from the end of the abdomen. The lower image is of a male, eyes set very close together and with a truncated, 'squared off' abdomen. The males also tend to be slightly smaller than the females.



DateSighting
25.05.2007 Found on bottom gate of hay meadow.
24.06.2012 Attracted, at night, to a moth lamp at Chambers Farm Wood nature reserve.


Snipe Fly, female Snipe Fly, female

a 'Snipe fly'

Rhagio tringarius agg.


Snipe flies are also sometimes known as 'Down Lookers' because they tend to land in a downwards facing position. There are over 20 different species and many can appear very similar.


While many flying insects can be positively identified by wing vein patterns, the whole Snipe fly family seems to have inherited very similar wing vein patterns. This means that determining a Snipe fly as a Snipe fly can be quite straight forward but, identifying which Snipe fly it is, can be quite a different matter.


The precise identification of this species is questionable since there are several 'look-alikes' with relatively unmarked wings that can only be positively identified under a microscope. However, labelling it as R. tringarius agg. (aggregate), acknowledges that it is representative of a group of species that includes R. tringarius.


Snipe Fly, male

The upper two images showing the sharply tapered and swollen abdomen and the separated eyes are of the same female. Whereas the blunt ended abdomen and close set, touching eyes seen in the lower image indicates that this image is of a male.


All of the Snipe fly genus favour areas of decaying timber in which the larvae thive - and we just happen to have a dead hollow tree and a brush pile nearby. Both adult and larvae are carnivorous. The 14mm adults taking other insects in flight and the larvae predating on grubs in rotten timber and the soil.



DateSighting
21.08.2004On the outside of a bedroom window.
26.05.2005On sting nettles at the base of a hawthorn hedge.
27.06.2008Found on coarse grass at the base of a hawthorn hedge.


Chrysopilus cristatus, female Chrysopilus cristatus, male

a 'Snipe fly'

Chrysopilus cristatus

The wing venation of this species is very similar to that of the Rhagio Snipe flies mentioned above and places this in the same family grouping.


The plump body and widely separated eyes of the 9mm long specimen in the upper image indicates that this is the female of the species. What is not seen here is that the abdomen curves down and under the body terminating in a distinct point.


Unfortunately the lighting does not do justice to the abdomen coloration which was a rather warmer creamy buff colour and was the feature that attracted my initial attention.


The much slimmer abdomen and close set eyes seen in the lower image indicates that this is a male.


The abdomen and thorax of young males and females can be covered in short creamy hairs but these tend to get worn off and mature specimens can appear almost bald.


They are on the wing from May to August and are widely distributed throughout the UK, being found in damp shady places, near woodland ponds for example. The larvae breed in rotting wood and damp leaf mould.



DateSighting
07.07.2005 Found resting on Water Figwort by the side of a ditch.
09.07.2008 Found close to pond in Horncastle Community Woodland.


Chlorops pumilionis Chlorops pumilionis

'Barley gall fly'

Chlorops pumilionis

These tiny flies have to be seen in context with the leaf stems of Salix caprea to appreciate how small they are. The male was only about 3.5mm and the female about 5mm.

Having taken the photograph was one thing, identifying them was another. It took me some 7 months to 'make the connection'.

There are two generations a year. The larvae of the Spring generation are considered to be a pest of cereal crops. They form gall chambers in the leaf stems of barley and wheat - and also couch grass, (an example can be seen on this link to the Galls Page 2) which render the stems non-productive.

A good image, detailing the wing venation, is to be found on this link.



DateSighting
30.05.2004Adults found on Salix caprea
20.10.20042nd generation larval galls found on Couch grass.


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Cleg, Horse fly
top view Cleg, Horse fly
side view

Cleg - Horse fly

Haematopota pluvialis

This is one of four species of Horse fly known commonly as 'Clegs'. They are regarded as a pest and nuisance to cattle, horses - and man. Notice how the wings are held parallel and close to the body.

The two sexes behave quite differently. The male flies with a busy drone and can be quite cumbersome in flight, bumping into objects. It relies on pollen, nectar and tree sap for sustenance. So, apart from his annoying habit of buzzing round your head, he barely warrants his bad reputation.

The female, on the other hand, is silent in flight and very light-footed. It is quite likely that she could land on you, un-noticed. However, she is adapted to suck the blood of horses and cattle - and with mouthparts capable of penetrating animal hide, human skin offers little resistance.

The lower image shows the extent to which the sabre-like mouthparts can be extended. As with many biting insects, the penetration can be accompanied by a local anaesthetic which often leaves the victim unaware of the attack until later, when the angry and irritating swelling develops. Some severe symptoms may require medical attention.

An insect with such a nasty reputation must have some redeeming features - just look at those psychadelic eyes!

It normally flies from May to September and favours damp habitats. It is reknowned for its annoyance to anglers and the wet moors of Western Scotland but, can be found universally throughout the Palearctic region from the UK eastwards to Japan.

The larvae are ground dwelling grubs living carnivorously on other grubs, insects and worms.



DateSighting
21.07.2006 Indoors, but not for long, and back garden.


Horse Fly

Horse Fly

Chrysops relictus

This sorry looking specimen was found on an indoors window sill. It was well dehydrated and must have been there some time.

For an excellent image of its natural state this link is recommended.

It is a colourful member of the Tabanidae family of Horse Flies and Clegs, with prominently marked wings.

At 15mm in length this was probably a large female.



DateSighting
11.08.2004Corpse found on indoors window sill.



Sicus ferrugineus

a Conopid or
    Thick Headed fly

Sicus ferrugineus

Although this species is classed as 'common', i.e. widely distributed throughout the UK, I have only ever seen it on the one occasion. It is certainly a distinctive species and with its widely spaced prominent eyes separated by yellow facial hair, it lives up to its common name of a 'Thick Headed fly'.

It is to be found from May through to September, flying around rough grassland, especially near flowering plants that attract bumble bees.

It is a parasite of bumble bees, actually laying a solitary egg on the bee. Considering how busy and active bumble bees can be when foraging for pollen, this is no mean feat. On hatching, the larva matures inside the bee.



DateSighting
31.07.2006 Seen at rest on brambles growing through a south facing hawthorn hedge.


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Picture-wing fly,
Tephritis formosa Picture-wing fly,
Tephritis formosa

'Picture-wing fly'

Tephritis formosa


Tephritis formosa is one of about 38 different Tephritidae 'picture-wing flies' found in the UK. Some of which can have very dramatic wing markings. They tend to be small - this one is barely 6mm long.


Small maybe, but very active. Many were found attracted to the honeydew from an aphid infestation but, they were never still for one moment. It proved quite difficult to focus the camera on one before it moved on.


The male's abdomen is quite rounded whereas the female's terminates in a tapered ovipositor, which is used to lay eggs in the base of Crepis (Hawksbeard) and Sonchus (Sow-thistle) flower heads causing grub gall chambers to form.


In the absence of pointed ovipositors, both these specimens are male.


The lower image is of a specimen found indoors in mid March. Given that it was in good condition and spent much time grooming itself rather than nervously flitting about, it is tempting to suggest that it may have recently hatched.



DateSighting
13.08.2006 Many found attracted to honey-dew from an aphid infestation on Salix caprea.
12.03.2009 Found indoors on a window.


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Platystoma seminationis Platystoma seminationis, male

no common name

Platystoma seminationis


This tiny fly, only about 6mm or 7mm long, behaves quite differently to the previous species. Whereas that one was all action, never still for one minute, this one moves quite slowly and gives the impression of being sick and infirm. If disturbed it will simply hop to a new location rather than fly.


The way it carries its heavily patterned wings in a half open, slightly raised fashion also enhances the 'sick' appearance. It just does not look well. If one were to describe it in human terms one would imagine it to have half closed eyes and a tired, dejected appearance.


It is quite common in southern UK, less so in the north. It is found in a wide range of habitats but, due to its coloration, small size and sedentary lifestyle it is often overlooked. The adults live off pollen and nectar and can be found around compost heaps and dense hedge bottom damp vegetation during the months of May to October. Breeding takes place in decaying vegetation on which the larvae feed.


Males are recognised by their truncated abdomens, females have pointed ovipositors.



DateSighting
08.06.2006 Found in thick undergrowth at the base of a Hawthorn hedge.
20.05.2009 Many found, mainly on nettles in thick undergrowth at the base of a Hawthorn hedge.



Palloptera muliebris

A picture-wing fly

Palloptera muliebris
..... ex Toxoneura muliebris.

The term 'Picture-wing fly' is a fairly loose term encompassing flies from several genera which have distinctively marked wings. Many of the species have a characteristic way of opening and closing (twitching) their wings in what might appear to be a nervous manner.


This species is widely distributed throughout England and Wales and favours damp wetland habitats around pond and stream margins and is to be found between May and October. I have found the fly supping honeydew deposits from aphid infestations.


Palloptera muliebris

Palloptera muliebris is characterised by holding its wings well away from its body, often at right angles to the body and tilted forward, as in the lower image. Perhaps this challenging attitude is used to compensate for it's small size, only about 5mm long.


Very little information is available about it's lifestyle but if it behaves as other members of its family, it is likely that the larvae will predate on small insects. They have been found under bark in the frass and workings of beetle larvae.



DateSighting
01.10.2009 Found on vegetation by garden pond.


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Picture-wing fly,
Herina longistylata

no common name

Herina longistylata

The flies known as the Picture-wing flies come from three distinct families - the Tephritidae, Ulidiidae and the Otitiidae families. This one is a member of the Ulidiidae.

There are two very similar species, Herina longistylata and H. lugubris but the former is much the more common and likely candidate.

This is a very small fly, not much more than 4mm, and can be found in two quite different habitats. One is dry calcareous grasslands and coastal cliffs (the grassland here-abouts is calcareous but not noticeably dry), the other is woodland streamside vegetation and damp scrub (and that more closely fits the local conditions).



DateSighting
04.08.2006 Attracted at mid-day to a wine lure used (unsuccessfully) to attract previous night's moths.



Bee-fly Bee-fly Bee-fly

Bee-fly

Bombylius major

There are some five Bee-fly species to be found in the UK and this one, Bombylius major, is widespread and the most commonnly found.


With its wings having prominent dark markings along the leading edge, this is probably the easiest to recognise as well. They have a body length of 10 - 12mm and will be found flying from March to June.


The sturdy proboscis that sticks straight out from the head should not be confused with a sting. It is quite harmless, being little more than a 'drinking straw' developed to reach deep seated nectar. Bee-flies will feed from a wide range of flowering plants and depending on the shape of the flower, will either rest on their spindly legs or hover like Humming-birds in front of the bloom.


Their plump hairy bodies make them look more like bees than flies and their fast wing beats produce a hum slightly higher in pitch than that of a bee. Their flight tends to be jerky and erratic compared to the more deliberate and purposeful flight of bees.


Their reproduction is somewhat unusual. Bee-flies are parasitoids of ground nesting bees. In itself, this is not unommon, many species invade bee underground nesting chambers and deposit their eggs in the chamber or on the bee larvae.


But, the Bee-fly simply deposits her eggs close to the tunnel mouth, leaving the tiny newly hatched fly larva with the incredible feat of making its own way down the tunnel and burrowing through the bee's egg chamber wall. It then enters a period of dormancy, allowing the bee larva to develop. Only when the bee larva is large enough to sustain the fly larva, does the fly larva awake from dormancy and attach itself to the bee grub and then proceed to suck it dry.


It will then pupate and overwinter underground. But, before it can hatch as an adult fly, the pupa has to wriggle and chisel or scrape its way out of the egg chamber using tough, sharp pupal spines. Only when it has broken through the chamber wall will it transform into it's adult state and make its way to the outside world.



DateSighting
22.04.2006 Found feeding from Lesser Celandine flowers.
10.04.2009 Three found feeding from Auberetia and Pulmonaria flowers.
11.04.2012 A least a dozen feeding from Auberetia and Pulmonaria flowers in warm sunshine.
23.04.2013 A least five feeding from Pulmonaria flowers in warm sunshine.
05.04.2014 Bee-fly found at rest on grass having presumably just emerged from underground pupation.



Euthycera fumigata, slug killing fly

a Slug Killing fly

Euthycera fumigata

Euthycera fumigata belongs to the Sciomyzidae family of flies which are generally considered to be Snail killing flies - the fly larvae parasitising the snails. But E. fumigata has a narrower niche in that it targets slugs rather than snails.

With the fine 'netted' appearance of its closely overlapped wings it is noticeably slimmer and presents a different appearance to most other flies in the Diptera family.

The specimen shown was 14mm long. The rather unusual antennae give rise to it being referred to as a 'Horn Fly' in Germany.



DateSighting
19.08.2007 Found on Salix caprea pendula close to garden pond.



Opomyza florum, female Opomyza florum, female

Stem Boring fly

Opomyza florum

This is a small fly. From head to folded wingtip it measures only 7mm. The head / body length being 5.5mm. All of which means that the enlarged images show features that may not readily be seen with the naked eye.

Perhaps its more noticeable features are that it walks slowly and is reluctant to fly. It is quite common and widespread throughout the UK and it can be found all year round although it is more numerous during the months June to October. The specimen seen here was found on a cold December day.

The images seen here look darker than some others on the web and may be due to seasonal variation (many insects take on darker colours in the colder months) or possibly to regional or food plant influences. But, the wing markings are consistent with the species identification.

The female bores a small hole in selective grass and cereal stems in which it lays an egg. As the larva feeds on the stem's interior tissues this results in stunted growth and in high population times this can cause significant cereal crop damage.



DateSighting
08.12.2008 Found on garage wall close to coarse grass covered field drainage ditch




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