Tachinids

[JRsbugs]

I have a few, tried to upload 10 pics and got one!

To start with, on 27th & 28th July, more today, I think this is Phasia barbifrons ~3mm on Achillea

More to come!

Janet

[Matt Smith]

Yes - yellow haltres make this P.barbifrons, not P.pusilla

Matt

[JRsbugs]

It was the hairs between the eyes I was going on Matt, but I don't know all the details.

I'll upload a couple more now.

[Matt Smith]

Originally Posted by JRsbugs

It was the hairs between the eyes I was going on Matt, but I don't know all the details.

I'll upload a couple more now.

The haltre colour is a good character that can be used in the field to separate the 2 smallest species of Phasia.

I would not like to make a determination between the two based on the amount of "hairyness" between the eyes unless it was a very detailed picture of the face. The difference between "parafrontalia bare outwards to a double row of facial seatae" (P.pusilla) and "prafrontalia setulose outwards" (P.barbifrons) is not really evident in the field photos.

[JRsbugs]

If I knew which part the parafrontalia was I might be wiser! I have a Tachanidae chart with names so will see if I can find it. I took more pics yesterday but have to edit them, I was determined to get the face but with such a small face, very dull weather and winds apart from fly walking and me wobbling it wasn't easy! I did check one pic showing the haltere, it looks more cream than yellow but I'll post that later. Good job you told me as it might be the other!

I think this one doesn't present problems. Phasia hemiptera male on 25th July, I got a worn female not long before and a fresh one in spring but have to dig those out. I saw the male the following day briefly.

[JRsbugs]

Phasia obesa I think! I had it down as 5mm but it might be more like 4.5mm.

25th & 27th July

[Matt Smith]

Originally Posted by JRsbugs

Phasia obesa I think! I had it down as 5mm but it might be more like 4.5mm.

25th & 27th July

Yes- this is P.obesa - a male. Next size down from P.hemiptera but bigger than P.barbifrons, male wings are shaded but no yellow hairs on the thorax.

What is this Tachinidae chart you have?

[JRsbugs]

This site on Tachinid Morphology, giving named parts.

[JRsbugs]

Matt,

This Phasia I got on 29th July and I think it's all the one fly. I did see two the next day but both had yellow halteres.

This looks to have a paler halter which is visible in one pic. You might be able to see the facial setae if you click again on the pics.

[Matt Smith]

Originally Posted by JRsbugs

Matt,

This Phasia I got on 29th July and I think it's all the one fly. I did see two the next day but both had yellow halteres.

This looks to have a paler halter which is visible in one pic. You might be able to see the facial setae if you click again on the pics.

The best and easiest character to separate the 2 small species is the haltre colour, its pretty "big" and shows up well in pics as like you have here. For the bristles, we are talking microscope level (20-30x) magnification being needed to get a confident "yes / no" of the facial bristles. I can see lots of hairs in the pictures, but not down to the point where I can look at the surface of the head to see exactly where the bristles start. Stick with the haltres.