The Society for the study of flies (Diptera)

Gateside · 2017-12-28 13:00:55

I used the Lonchopteridae key by Kenneth Smith, and (rashly?) took the Lonchopteridae challenge, using images alone.
I went wrong (or took different routes) at least twice, but have produced below my preferred solution.

Here are my rough notes:

Mid tibia, ad in distal half - see image 3308-legs (or 3313-legs). No sign of any other bristles except apical one.

No av spines, so therefore => 4

Scutellum not intensely black - normal black? Middle pair of vertical bristles pale? (3313). Outer ones are mainly pale.
=> 5

Large dark species. (yes!)
Mid tibia is bent slightly near base (3315, 3317). Basitarsus is more than half length of tibia ? Not sure, but does look good for both front and hind basitarsus / tibia ratio.

=> Lonchoptera tristis female.

Any positive comments? (some images are obviously enhanced regarding lighting level, but image info is still essentially unaltered)

Nigel G.

Uploaded Images

Last edited by Gateside (2017-12-28 15:08:41)

Tony Irwin · 2017-12-29 12:50:14

Nigel - I think you need to look again at couplet 5. L. lutea is a very variable species and although tristis tends to be larger, they can be much the same size. Colour-wise, your specimen is quite dark, but I would expect tristis to have a darker frons and face. The mid tibia in female tristis is slightly bent at the basal third, but bent so that the anterior face becomes concave. Whatever bend is present in your specimen appears to be the other way round. The mid basitarsis in tristis is about 2/3 the length of the mid tibia. Even allowing for odd angles, I'd say your mid basitarsis is struggling to reach half. As you suggest, it's easier with a specimen! But I'd plump for lutea with this one.

Last edited by Tony Irwin (2017-12-29 12:50:51)

Gateside · 2017-12-29 14:41:24

Thanks for your thoughts, Tony. Clearly experience counts quite a bit in this area.
It seems that you are aware of additional information which isn't in the key as such.
At couplet 5, I'm not surprised I went wrong on the basis of the overall darkness of the specimen (I have never seen such a dark one).
That I got the bend wrong doesn't surprise me either - it doesn't say! I don't have a great view of the mid leg to base comparative lengths on, but it looked quite promising for the fore and hind legs.

I'm not sure this is actually good enough for logging. I suppose I could submit it as a "likely", but on the other hand the veriifier probably has enough to do, without an additional slightly iffy record for a common species. ..

(And I have recorded L. lutea here in the last year anyway!)

Last edited by Gateside (2017-12-29 14:45:45)

Tony Irwin · 2017-12-29 15:43:05

I think if you have already recorded lutea at this site, I would let this one go.

Howard Bentley · 2017-12-30 17:06:56

I remember being similarly confused by a very dark specimen of L. lutea some years ago. Fortunately Roger Morris was on hand at the time to put me right. This species is very variable in body colour, though not, I think, in the colours of the head bristles.

Gateside · 2017-12-30 22:10:06

to both Tony and Howard!

KenMerrifield · 2019-09-30 14:41:54

I have closed this topic as somebody/something keeps posting the same spam-linked message for an essay writing service. I have deleted and banned the re-registered users about four times and hope this will discourage further attempts.

The Society for the study of flies (Diptera)

#1 2017-12-28 13:00:55

Lonchopteridae ID query

#2 2017-12-29 12:50:14

Re: Lonchopteridae ID query

#3 2017-12-29 14:41:24

Re: Lonchopteridae ID query

#4 2017-12-29 15:43:05

Re: Lonchopteridae ID query

#5 2017-12-30 17:06:56

Re: Lonchopteridae ID query

#6 2017-12-30 22:10:06

Re: Lonchopteridae ID query

#7 2019-09-30 14:41:54

Re: Lonchopteridae ID query

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