I'm going to be a Daddy!

I say 'Daddy' but actually...

Eleven days back, I took myself down to Portree and enjoyed a slow wander through the woods, finding myself a whole bunch of leaf-mining fly larvae. I blogged about it that evening, doubtless you recall the post in question. No? Ok - here's the link for you. Amidst various other things, I found a single Phytomyza ranunculi larva in a Creeping Buttercup leaf, which I promptly popped into a pot. Later that same evening I extracted the larva from its mine and took this pic

Yellow maggot of Phytomyza ranunculi

I bundled the larva and buttercup leaf back into the glass tube and hoped nature would run its course. That was eleven days back.

Spoiler alert - don't read the (really rather squiffy) label just yet

Miraculously, the larva survived and successfully found its way back into the leaf tissue whereupon it continued munching its way towards being fully fed. I didn't check the tube yesterday, but I had a peek tonight. This is what I found

The upper tube is the  Phytomyza ranunculi larva - look closely now!

Here's an even closer look...

Still can't see it, huh?

My Phytomyza ranunculi larva has successfully pupated! Woo-hoo, that's my boy!

I've still to wrap my head around the whole process of a larva turning into an adult insect. In this instance, the maggot reduces into a gloopy mess and then somehow reconstitutes itself into a fully-functioning fly complete with compound eyes, bristles, legs and wings. The two pointy things visible at the either end of the pupa are the breathing spiracles, it's how the maggot/pupa breathes. By the time the adult fly emerges, these spiracles will be situated one at the front and one at the rear of each side of the thorax, providing oxygen to the massively enlarged flight muscles. I have ABSOLUTELY NO IDEA of the processes involved in this metamorphosis. Various experiments with caterpillars have conclusively proven that adult butterflies have memories of being a larva, presumably the same also holds true with flies. It seems that the central nervous system and the brain remain essentially intact and functioning, whilst the surrounding body tissues reduce into a 'soup' before settling out into the radically different adult form. Pure voodoo rootwork if you ask me.

Anyway - I shall be keeping a close eye on my pupa. It's ordinarily pretty cold in my room (though a lot warmer than current outside temperatures - we enjoyed a good snowfall yesterday) so it should take a wee while for the adult fly to emerge from the puparium.  The other tube visible in the pic above houses a busily chomping larva of Chromatomyia aprilina in a Honeysuckle leaf. Hopefully I'll be able to rear that through to adulthood too. Usually I end up with a parasitic wasp, but somehow I'm hopeful of rearing through adult flies this time, we shall see. 

For Hendrix fans out there, never mind that Voodoo Child rubbish, here's a 1969 clip of a truly stoned yet phenomenal Jimi performing Voodoo Chile . It's not a short clip, so settle back and please enjoy! 

How I Pin Small Flies

This post is in response to a couple of questions received from Martin. Hopefully it will prove useful to anybody else reading this too, just to show that using micropins on tiny flies isn't necessarily a Dark Art best left to the professionals. Without doubt, I'm one of the clumsiest, butter-fingered, accident prone people out there, if I can do this then so can anybody. All you need are the right bits of kit.

I almost entitled this post "How To Pin Small Flies" but that would infer that I knew what I was doing and was following official guidelines, whereas in fact I just do it my own way which may be right or may be wrong. So here goes an account of this morning's exploits with a fungus gnat.

Sorry for the date stamp, I was playing with my new camera!

This is inside of the laundry shed I keep waffling on about. Usually there are laundry bags piled up everywhere, but it's empty at this time of year whist the hotel is closed for refurb. I painted the walls and ceiling last year to enable me to spot small insects more easily. Naturally, that's not quite how I put it to the bosses at the time...

A particularly well fed spider lives behind the edge of the bulkhead light!

Anyway, I grabbed a fungus gnat, plus two others, and brought it back where it was duly dispatched with a small dose of ethyl acetate. Here's a pic of the kit I use when pinning flies

Plus my microscope and a desk lamp!

If I was carding beetles I would dispense with the box of micropins and the strips of  Nu-poly and instead have my sheets of card, some glue and water, a small plastic lid that I use to mix them and a hooked micropin embedded into a match stick which I use to pull out legs and antennae etc. Most folks use a tiny brush for this but I prefer a hooked pin, presumably harking back to my days of microlep setting.

My micropin storage box

I used to keep my tubes of micropins loose in amongst various other bits and pieces of entomological paraphernalia, but occasionally the lid of a tube would work loose and I'd find hundreds of tiny pins strewn everywhere in the bottom of the Tupperware tub I kept everything in. So now I keep them all together in a plastic box which has a snap top lid. It just keeps them a lot safer and tidier and reduces the chances of spillage by about a hundredfold. As you can see, I labelled each tube with the different sizes of pin. I get mine from Watkins and Doncaster, so use their codes on my tubes which makes it a lot simpler whenever I need to order more. I use stainless steel headless pins which can be found by scrolling down here.

I have pre-printed labels that I use, all I need to do is fill in the date and add my name to the top label. The bottom label I fill out as and when I identify the beast in question to genus or species. If I can only identify it to family, I add a temporary label which could read, for example, "Chironomidae (625spp)". My hope is to replace these temporary labels with proper bottom labels, but some are unlikely to be progressed beyond family - or even superfamily - level anytime soon.

Right, so that's the kit. Now for the pinning technique itself. 

I lay the dead fly on a small piece of plastazote in the position I want it to sit on the pin. I decide which micropin size to use, this being entirely determined by the size of the fly and whether I intend to side pin or direct pin through the top. In reality, I almost always side pin small flies and almost always direct pin hoverflies but I tend not to follow hard and fast rules. It's a good idea to pin all flies that have been side pinned facing the same direction (ie left to right or vice versa) which not only looks neat and orderly in a storebox, but helps with direct comparisons with similar looking species. Sadly my flies are pinned facing every direction imaginable, something I need to work on improving.

All in readiness for side pinning. These happen to be A2 pins

There are a couple of tricks to pinning small, fiddly stuff like these. Without a doubt the most important being what you use to pick the pin up, followed by where to hold the pin as you move it. If you get those two things wrong you'll either end up pinging pins across the room, never to be found again until the day you step on it (lost micropins terrify me, I'm almost always walking around my room barefoot), or you'll find yourself unable to grip the pin securely enough to manoeuvre it around properly. This is my current weapon of choice 

The No.4 Superfine Stainless Steel Forceps

These forceps are not cheap (over twenty quid) but have been worth every penny. I've previously used blunt-ended or round-ended forceps with grooved tips to grip the pin more securely. And I used to drop lots of pins or send them twanging into oblivion, never to be seen again. But these fine-tipped bad boys are amazing, I hardly ever twang a pin nowadays. And it definitely helps to hold your forceps as close to perpendicular to the pin as possible; holding a pin with the forceps angled obliquely lengthwise along the shaft is far more likely to cause it to slip and ping away than if you hold it square across the shaft. One final word of caution; it is very easy to damage the tips of these forceps. I dropped mine onto the floor and bent a tip, resulting in my ordering a replacement pair since the dropped one could no longer grip pins properly. They come with a plastic sheath that sits over the tips when not in use which helps to protect the tips themselves and, as an added bonus, it stops me accidentally stabbing myself with them! Mine are always covered unless being used.

Back to pinning the fly

So here is my fungus gnat laying in the position I wish it to sit on the pin. I insert a pin into the plastazote next to each fly I am pinning (see previous pic above this one) making sure I have the sharpened tip at the bottom. That sounds pretty bloody obvious, but these pins are so very small and fine it's often difficult to see which end is which! I use my microscope to double-check if I'm not entirely sure. With the very smallest flies, a pin inserted upside down may badly dent the insertion point and will provide resistance when later mounting into a nu-poly strip, potentially enough resistance to bend the pin and send it twanging across the room never to be seen again. And taking your fly with it! So yeah, check the pin is the right way up, obvious as that sounds.

Note that I'm holding the micropin low down, almost where it is jabbed into the plastazote. I've discovered that this is a good, stable way of holding the pin and it reduces the effect of hand shake. Pins held right at the very tip nearest you will inevitably ping, so I hold them low down. You need enough pin exposed beneath the forceps to drive through the fly's body and into the plastazote beneath in one smooth action. Then, when it's securely held in the plastazote, slowly release the pin, raise the forceps further up the shank and push down some more until a good part of the pin has been exposed below the fly. Obviously there needs to be enough pin showing above the fly for you to be able to grasp it in your forceps and move it to the nu-poly strip.

Fly is now sitting roughly midway up the micropin

  

After that, it's just a case of inserting the pin into the nu-poly strip and using a mounting block to get the correct height for the strip and accompanying data label(s). Always make sure the nu-poly strip is firmly supported by a layer of plastazote when you insert the pinned fly (see pic further up the page) otherwise it will bend and the pin will go in at a funny angle. 

That's about it, really. I use a pinning stage to set everything at uniform heights but it's not completely necessary. I use a Pigma Micron 005 pen to write the data labels, which I've just found online here. These use a 0.2mm wide line of ink allowing me to write in clear but tiny lettering without any blurring or smudging.

Martin's second question related to the literature I use to get a fly to family. 

The Key to the Families of British Diptera by Unwin (1981) is available as a downloadable pdf or from various bookstores. I have the 1991 edition, which you can see in the image above. I'm not sure whether it's a reprint or has been updated from the 1981 edition. This is a good, easy to use key but should not be used for European flies as it is purely British orientated. I was warned that it doesn't always work out properly, and that proper grown up dipterists use the other book in the image above. So I went and bought that too. The European Families of the Diptera by Oosterbroek (2006) costs a whacking sixty quid, but it is just brilliant and if you really want to get into flies then you need to have this book, it's just that simple.

Diptera - Simuliidae

I swiped a small fly from the laundry shed wall a few nights back (I wonder how many other budding dipterists frequent laundry sheds of an evening) and tonight I finally whacked it beneath the microscope for a closer look. It was quite a weird looking thing and I was somewhat puzzled as to which family it belonged. The antennae looked decidedly Nematocera-ish, but it seemed rather a chunky monkey hence I wasn't entirely convinced. Distinctive wing shape and venation though.

Very well pronounced anal lobe and a distinctly S-shaped  CuA2 vein

  

It seemed to spill out of the key at Nematocera, confirming my initial thoughts, though definitely not a family I was familiar with. I mean, just look at those hind legs!

Laterally compressed but massively enlarged

Clearly it was a male with its hugely enlarged eyes, holoptic as it's properly known, which simply means that they meet in the middle at the top of the head. Typically it's the males that have these 'over-developed' eyes, seemingly an adaptation to holding position in a single sex mating swarm whilst keeping a (large) eye out for any females attracted by the prospect of finding a suitor. I've seen this in mayflies (Ephemeroptera) but I'm not sure which other insect orders, if any, display a similar sexual dimorphism.

Why grandpa, what big eyes you have...

Close up of wing-shape, the anal lobe and the overall rather odd wing venation

Happily, all of this led me to a single family of flies called Simuliidae, which are the Blackflies that sometimes bite us. Or at least the females do, this is a male and its mouthparts are entirely unsuited to piercing human skin. In fact the males imbibe nectar, though I'm not sure when or where this particular chap would have last found a meal around here! I hadn't realised blackflies were quite so large, this was easily 4mm in length (which is relatively large compared to most of the flies I've been finding recently), I thought they were tiny midge-type thingies. Seems not. I'm learning - good. 

Sadly, despite there being a mere 35 or so species on the British list, the Simuliidae are considered difficult to name to species, requiring both microscope slides of the genitalia and a 60-year old key that I don't currently own. It could be £15 well spent. But then again...

Simuliidae is my thirteenth PFL for the year. So quite a ways to go yet, though I'm blazing away from The Terror and The Ghost....

Sieving for Beetles

It's taken me almost three weeks, but finally I broke out my sieve and tray and hit the large woodchip pile that has been sitting in the grounds for several months. This was formed when two large Wych Elms were pollarded before they started dropping limbs onto cars parked below. The logs were split and stacked and the brash was reduced to this large pile of woodchips.

I gave it all of about five minutes before quitting with absolutely nothing to show for it. It just didn't seem right, maybe I needed to be in deeper, or maybe it needed to be warmer. Who knows? Anyway, I moved elsewhere which soon proved to be far more profitable

This is the smoking shelter I built for some staff last springtime, hidden away between the back of a shed and a steep earthen bank full of Scaly Male-ferns and a little bit of Bracken. At this time of year it's clearly a bedraggled mess, but in the summertime it's luxuriantly green and lovely. I figured it could be worth ragging out some of the dead stuff and shaking it over my tray

The

The smaller debris that has fallen through the sieve and into the tray

I wasn't honestly expecting a great deal in the tray, but it held a surprising number of spiders and springtails, a couple of flies and quite a few small beetles, staphylinids mostly. 

The results of just two shakes over the tray

The brown beetles in this image are all Anthobium unicolor. The short black one bottom centre is Proteinus brachypterus. The two elongated staphs to the left are aleocharines and are well beyond my current abilities. The fly in the middle is a sciarid, the first I've ever recognised and it turns out to be a complete and utter bugger to key through. In the end I quit trying - I need higher magnification, better lighting and a greater understanding of fly morphology.  

Beautiful looking, but a nightmare to try and key through to family

And the little black dot next to the sciarid's wingtips is a Ptiliidae, one of the featherwing beetles, rocking in at almost a whole millimetre in length. Here's a close up to prove it really is a beetle and not just a full stop

I'm gonna have to gen det this - wish me luck...

So, within a mere 30ft of my room, I sieved more beetles in two shakes of dead ferns than I've seen over the past three weeks put together! Clearly I need to start taking my sieving gear with me when I go out into the woods. Gonna need a bigger rucksack, that's for sure. And another storebox (or two) for the backlog of stuff I'm identifying to family level but not species. Hmmm. 

Loads of Agro(myzidae)

I had a day off work today and, unbelievably, it was decidedly pleasant outside. I promptly jumped into the car and headed off for a quick change of scene. I took myself down to Portree and headed into the woods behind the Cuillin Hills Hotel in the hope of finding some dipterous leafmines and maybe the odd beetle too. 

It didn't take too long to find leafmines, the very first Holly bush I looked at added a new fly family to my 2020 Vision List

Phytomyza ilicis - the only dipteran capable of surviving mining Holly leaves

The Holly Leafminer Phytomyza ilicis is dirt common across almost the entirety of Britain. Wherever you find hollies, you'll find the mine (unless you live where I am - it's totally absent here). I saw plenty of these mines throughout the woods at Portree today, it's very much an expected species for my 2020 Pan-fly List - 'PFL' (© M. Telfer). Legend has it that Holly leaves toughen up pretty fast, quickly hardening as they age which renders them essentially inedible. Most leaf-mining species that tried to tackle Holly would find themselves being sealed into a leathery grave, one too tough for their mouthparts to handle. Yuck! Phytomyza ilicis, however, is a prodigious eater and manages to eat enough leaf tissue (and fast enough) to develop into a fully grown larva before the young Holly leaf hardens up enough to trap it within. There's a much larger Tortrix moth that also feeds on Holly leaves, but always in the soft new growth and never in the old stuff. 

Also in the woods were a few mined leaves of Creeping Buttercup. For example...

The larva is the yellow blob at the extreme bottom right corner of the mine

There are several different species of fly that mine buttercups, so attention has to be paid to the dispersal pattern of the frass and the general track of the mine itself. Helpfully, the time of year is a huge bonus too. 

Peeling back the upper epidermis of the leaf reveals the larva within

The only British species that has buttercup mining larvae active during the wintertime is Phytomyza ranunculi, a common species across Skye. 

The maggots of leaf-mining flies do not have jaws (or legs), making them instantly recognisable from other potentially similar leaf-mining larvae such as those belonging to moths, sawflies or beetles. Fly larvae have what I call a 'pick axe' for mouthparts, they use this to hack off segments of leaf tissue before consuming it. Here's a short video clip of the larva above, watch out for the black 'pick axe' cleaving its way through the green tissue

Apologies for the background noise, that was a short clip of Kyuss you were listening to, or rather I was. 

So that was Phytomyza ilicis in a Holly leaf and Phytomyza ranunculi in a buttercup leaf. What else could I find? 

A tenanted mine on Honeysuckle

There are quite a few species of fly that mine Honeysuckle, I generally find them to be a bit of a pain to separate, so usually I don't bother trying. But this is Vision 2020 and every fly needs to be nailed to species, hence I bothered.

There are several websites dedicated to leaf mines and their causers, not just dipteran, I have them all bookmarked on my laptop. The ones I visit most are:

The Leaf and Stem Mines of British Flies and Other Insects 

British Leafminers

Plant Parasites of Europe

Each of these are excellent, though there's quite an overlap of text and image usage between them. Clicking onto Lonicera (Honeysuckle) will provide a list of species utilising that host. Keys or links are provided and all you have to do is see which fits your specimen and doublecheck between sites, NBN and various other websites to make sure it all fits together neatly at a given species. Hopefully you don't have to rear your larva to adulthood, something I'm not very good at. 

The problem was, nothing quite fitted my mines (I found several). However, a little over ten years ago it was noticed that winter-active flymines were being found on Honeysuckle which didn't really conform to any known British species. Investigations were undertaken and it transpires that there is a winter generation of Chromatomyia aprilina larvae that have differently produced mines to those of the summer generations. The big clue is the colour of the larva itself

Larva is at the end of the upper left section of mine

Exposed for the world to see

Clearly it is a pale green colour, whereas all of the others in the genus are off white. So that's Chromatomyia aprilina on the list too. Good stuff.

The one fly mine that I was fully expecting to find was Chromatomyia primulae, which occurs on Primrose leaves and is another very common species. I did locate several old, vacant mines plus one tiny aborted mine, but none were tenanted. Weird. Numbers of mined Primrose leaves seem very low this year. But I'm not worried about missing it, I'm certain I'll find plenty as the year progresses.

For anybody wondering if I've even bothered looking for beetles recently, yes I have. And I found one whilst in these woods. Found in the middle of a pretty rotten Birch Polypore Fomitopsis betulina

Tiny - note the size of the lines in my palm! 

So that's my homework for the rest of tonight - trying to ascribe this beetle to the correct family. I know it's a staphylinid, but there are rather a few to work through. I suspect this will not be easy! The fact that it's about 2.2mm long doesn't help any. Maybe I could use my compound microscope..?

Edit - I THINK it's Aleocharinae. The tarsal formula appears to be 5,5,5 - certainly the mid and hind legs are 5,5 so the front legs should be too (seeing as none of them are 3,5,5 or 4,5,5). Regards the pronotal pubescence patterns, or the Pronotal Behaarungstypen, I'm not sure whether I'm seeing type II or type V. Either way it's just sitting on a card for now. One for the dim and distant future, I suspect!  

This is a great band, the drummer's wife used to work with my ex in TGI Fridays. I give you The Enemy - Aggro(myzidae) Enjoy! 

Gnat Dissection

Miracle of miracles, today Skye was spared sideways lashing rain, hail and gales. It was still a bit blowy, but totally bearable outdoors in just a hoodie. I had high hopes of finding flies attracted to the security lights once darkness fell (about 4pm today...it's still very gloomy and cloudy) and sure enough a quick peek at the nearest light revealed several small flies/gnats lifting at my approach. Undeterred, I filled eight pots with a small fly in each - an absolute bonanza!  

Awaiting the ethyl acetate treatment

My method of dispatching flies is quite simple. I add a small wad of tissue paper into the top of the tube, pipette a few drops of ethyl acetate onto the tissue, replace the lid and wait ten minutes. Job done.

Simple and efficient

Previously, I've had a dedicated killing jar (I use an old jam jar) into which I've tipped the captive flies. The obvious problem being that sometimes they fly up and away in a bid for freedom, often straight out the window never to be seen again. My current technique is heavier on ethyl acetate usage but I suffer far fewer escapees. I suppose I could chill them in the fridge and then tip them into a killing jar, that might be even better. I'm not a fan of killing insects by freezing, I've heard that various internal organs may distort, and the genitalia are often critical for a positive ID. Wouldn't want them to swell/twist/split on me.

Of tonight's eight flies, two are Moth Flies (Psychodidae) and there were plenty of those running around the whitewashed wall below the security light. I do actually have a key to these but you need to clear and dissect the body and mount it on a slide. I may have a go (in fact I'm sure I will) but not tonight. For now they are simply labelled "Psychodidae (100spp)" awaiting another day. Crazy mad antennae on them though.

I have a handful that I'll look at tomorrow and there are three Trichocera, the Winter Gnats. I've sussed these now, the gangly legs holding the body poised as if ready to flee (which they often do) and the short, downcurved anal vein that reaches the wing margin make for an easy recognition of the genus. Males have obvious claspers and the females a horny ovipositor, both of which are of a size and shape unique to the various species. Add in wing clouds and lengths of various veins in the wings and an identification should be relatively straightforward. 

First up I checked a male. No wing cloud over r-m, so it's not Trichocera regelationis, the only one of the genus I've seen before (ticked earlier this week, in fact). It keyed through without any problems to Trichocera major, the largest British member of the genus. Here's a pic of its claspers

The long sinuous styles are classic male Trichocera major

Next up I looked at a female Trichocera. No wing cloud over r-m, big old ovipositor, looks good for Trichocera major too. Sweet. Here's a pic of the long ovipositor

I whacked the pics on the UK Diptera FB group for confirmation and pretty soon Julian Small, the resident Nematocera expert of the group, came back with the male is T.major but the female isn't!!! Oh, ok. I keyed it again, paying close attention to everything before leaping off to another couplet, this time it led elsewhere. Oops. I now made it saltator. Julian had obviously come to the same conclusion, for when I checked FB next he'd responded with

Maybe it's just an individual variation, or maybe it's saltator. I reckon there's a good chance of unrecorded species in the more wild and woolly parts of the country. Do you fancy dissecting out the genital plate?

Did I fancy tearing the arse out of a gnat, my first ever fly dissection? Well of course, whatever else would I be doing on a Thursday evening. Seemingly all I had to do was tease apart the last abdominal sternite and tergite and the plate would be sitting there flat and ready to view. How hard could this be?

A few minutes later and...

It's the black 'pincers' with pale 'shield' that make up the genital plate

I wasn't entirely sure I had the right part, but it looked vaguely like the drawing Julian had sent, along with this sublime line: 

This is what the saltator female genital plate would look like. It's only ever been seen by some of the world's most boring people.

I tried to line it up a bit better for the camera when disaster struck as it pinged across my desk and disappeared into who knows where. Bearing in mind that the entire thing is substantially less than a millimetre across, I had little chance of finding it again. Damnation.

Luckily, Julian was happy that this image confirmed my female gnat as Trichocera saltator. He then dropped this rather large bombshell into my lap

That's the one. The top looks good for saltator. The critical bit is the thickness of the neck of the black 'stalk', which is just out of sight. Think it is saltator though.

As far as I know, you're only the second person in the UK to do this dissection!

Haha!!! So I'm officially one of the world's most boring people - result! 

Getting some Help

I had a great evening last night, and all because of one small fly. My obligatory after dark visit to the laundry shed found me eye-balling a fly sat on the light itself - and I mean a 'real' fly, not a midge or a gnat this time. Excitement levels were high as I gently slipped a pot over it and safely snapped the lid into place with the fly still inside. Cool, but what had I found this time?

Back indoors I found myself looking at a grey and yellow fly with skinny legs and long wings. No idea which family, so I ran it through the keys and it came out at Heleomyzidae. Great, I just need to find a key and give it a whirl...

Which is as far as I got for some time. The only key to Heleomyzidae that I could find was one to the genus Suillia and there are fourteen more genera in Heleomyzidae that I needed to work through. Time to find some help. Gilbert's Ghost had told me to ask if I needed anything, he has lots of fly-related literature including some quite obscure stuff. So I asked and he very quickly came back with a key. To Suillia. Grrrrr. Different key, to be fair, but same genus. I went back online and came up blank once more. The only literature that folks kept quoting were Collin (1943b) and a draft version to the family handed out a few years back at a workshop. Neither available online or to buy. Bugger, now what. 

The Ghost suggested I whack the pics up on iRecord, but I fancied my chances on a Facebook group first. These are the three images I added online, with a request for either key previously mentioned or a heads up to other keys that are still available. 

Two (not one) orbital bristles tell us that this is not a Suillia

It's a very smart fly, I spent quite a while visually exploring the various bristles and spines and whatnots. Blimey, it seems that I'm quite getting into this fly malarkey! 

After a short while I received a message from an extraordinarily helpful chap (a proper grown up dipterist, in fact) who pinged me across a modern key to Heleomyzidae. What a hero! With this key I would be able to ID the mystery fly, or so I hoped. 

Before I could make a start with it though, a second chap commented on my post and told me the sex and genus involved. Coolness! He too is a proper grown up dipterist, and a very good one too.

First thing I did was run it through to subfamily, it came out at Leriinae which I've never even heard of. Happily, there are only three genera in Leriinae and one of them matched what the dipterist said on my Facebook post. Even better than that, I scrolled down and discovered there are only FOUR species in the genus!! This would be a doddle. 

More pics for you

Dorsal preapical bristle on hind tibia - quite an important feature

Quite the looker - note the concave profile beneath the antennae

The single pre-sutural dorsoventral bristle (by my red dot) helps ID this to species

The only other feature I now needed to see concerned the precise placement of a line that runs between the front orbital bristles. Was it closer to the front ocelli or was it closer to the front of the frons? Two options leading to two species. I had to get this right.

Just look at those colours! Absolutely gorgeous!

The line in question is the narrow dark one separating the golden top half of the face from the orange lower half. Does it lie closer to the front ocelli (the three tiny 'eyes' in the silver triangle) or does it lie closer to the arched lower edge of the orange patch? I knew what I thought, but I measured anyway. It lies closer to the front ocelli.

All of which means I can confidently identify this fly as a female Heteromyza commixta, a widespread species and possibly more common in Scotland than in England. The NBN Map would suggest otherwise, it would also suggest it is new for Skye. Whether that's true or not I don't know, though I doubt it. What I do know is that it's new to me and I have a friendly online dipterist to thank for supplying me with a key. 

Sometimes it really is good to just ask for help. 

First New Fly of the Year!

I performed my nightly inspection of the laundry shed walls and ceiling, and drew a blank for the second night running, so then I checked beneath several security lights and found a leggy gnat perched on the wall beneath one. I quickly potted it up and returned indoors to see what it was I'd caught this time. 

It was somewhat larger than the midges, fungus and window gnats that I've been seeing this week, emphasised by its hugely long legs. Here's a pic of the beast in the tube

I was one of seven folks heading home through Wimbledon Village in an old Ford Puma once, I reckon my knees and elbows were bent up in the air in a similar fashion to those of this fly. Here's the car I'm on about. Seven of us, ha! 

It really is just as well the police never saw us...

Anyway, back to the fly. I ran it through the keys and went wrong. Huh? Going back I checked and had to double-check again the top of its head, which had collapsed in on itself despite the fly only being dead for a matter of minutes. Weird. But, eventually, I saw that it did have ocelli and took it back through the key. Very tricky to discern indeed. From that point onwards it ran straight to Trichoceridae, which I knew it would. I've been keeping my eye open for a species of Trichocera all week. In fact, I half expected it to be my first diptera family of the year, even though I've never identified one before.

I found an online RES key to Trichoceridae and within a very short space of time had it down to genus and then species. Check out the (admittedly rather vague) dark cloud over vein r-m

Vein r-m is the short upright(ish) bent one in the middle of the widest part of the wing

And here's a pic of the claspers, it being a male

I definitely need to improve on my microscope pics - sorry! 

All of which leads to a robust identification of Trichocera regelationis - a new fly and a new family for me. According to the NBN Atlas it's also new for the Inner Hebs. Excellent, who knew gnats and midges could be so cool?