Is this a Tachinid fly

[Ollie]

Hi all

Can anyone confirm this is the Tachinid fly - Tachina fera or am I on the wrong lines completely. Please click the image twice for best detail.

Thanks in advance.

[Dogghound]

No its a muscid Helina impuncta

[Ollie]

Many thanks for that Dogghound

[Jason Green]

Afternoon Colin/all,

Well, I find this group pretty scary, ID-wise. For the purposes of education what is it about this fly that makes it Helina impuncta - pre-occular bristles, basi-tarsal seta or something?

Tae care,

Jason

[JRsbugs]

Originally Posted by Jason Green

Afternoon Colin/all,

Well, I find this group pretty scary, ID-wise. For the purposes of education what is it about this fly that makes it Helina impuncta - pre-occular bristles, basi-tarsal seta or something?

Tae care,

Jason

It just looks like it.

With some muscids, leg colour, halter colour and those big things behind it , general overall colour are some of the things to go on, that is for the easier ones.

Janet

[Jason Green]

Ah... but why impuncta as opposed to another, and what source states these are the trademarks of this particular Helina sp.? Just interested!

[Bruce Williams]

If I've read Janet correctly the "big things" behind the halter are called "calypters". I've often noticed them when I've been working on a fly image and equally as often have wondered what function they perform - anyone know?

Bruce

[JRsbugs]

Originally Posted by Jason Green

Ah... but why impuncta as opposed to another, and what source states these are the trademarks of this particular Helina sp.? Just interested!

The source is me, I just told you.

If you have been watching flies being identified off and on for at least 4 years as I have, also been looking at them in the diptera galleries each time I wanted to know what a fly is, and put some up for ID, well you might get the gist..

I think these are easy compared to Anthomyiidae where it usually depends on which bristles are where, and other things if visible and if possible from a photo. It takes a lot of looking, more so than relying on keys for a start, you need to get the eye for it and to know what to look for. That takes a lot of researching, late nights/early mornings. Even then there's still so many things to learn and that can't be done overnight.

Bruce, I found something which might help explain the use of calypters, otherwise known as squama I believe.

I have seen a suggestion that the calypters function to mimic the sounds produced by bees and wasps. The posterior calypter somearial covers the halteres so I suppose can increase the buzzing sounds.

From here

Whether or not that's the case I don't know, but from searching after prompted by your question I am once more learning!

The halteres serve as balancing mechanisms.

This is the sort of thing which can help anyone's understanding of identification, even if you don't have the keys. Not that I spend all my time looking at flies, I look at other things too!

[Jason Green]

There seem to be at least 38 Helina spp. in for the UK, so what I'm really trying to get at here is what has excluded Colin's fly more specifically from the other 37+.

I have one that looks similar, and would just like to know the more technical points that make it impuncta as opposed to one of the others

[JRsbugs]

I think it's the bright yellow calypters apart from the other details such as leg colour etc. That's what has stuck in my mind anyway!

Good point though Jason, so I searched on diptera.info for some other clues on previous threads (something you can do and it's a good idea).

I guess in the case of a faded or newly emerged fly there might be some doubt. Some flies are also more commonly seen.