Thread subject: Diptera.info :: Stratiomyidae, Beris

Posted by MorganA on 08-11-2023 21:59
#1

I am a bit puzzeled about this Beris, I thought either chalybata or morressii, but the narrow frons that clearly widens towards the antenna makes me confused.

South Norway 20th July 2023

Posted by MorganA on 08-11-2023 21:59
#2

2

Posted by MorganA on 08-11-2023 22:00
#3

3

Posted by Zeegers on 11-11-2023 08:54
#4

I don’t see the problem. Vertex is the uppermost part.

Theo

Posted by MorganA on 11-11-2023 19:21
#5

Well, I have not seen that many B. chalybata or morrisii, but compared with the ones I have in my collection it seems so off. I took a picture that illustrates how different it is from the B. chalybata and B. morrisii I have in my collection

Edited by MorganA on 11-11-2023 19:22

Posted by Zeegers on 12-11-2023 18:26
#6

All these have completely yellow legs ?

Theo

Posted by MorganA on 12-11-2023 19:19
#7

All of them have completly yellow femur and tibia yes. I add a lateral pic of all of them as well.

Posted by Zeegers on 12-11-2023 22:27
#8

OK, interesting. so the one top right is clearly morrissii, and the others are clearly not. Note the difference in the green.
in the other two, the antenna is remarkably slender, so I am wondering if these might be geniculata.

Theo

Edited by Zeegers on 12-11-2023 22:28

Posted by MorganA on 13-11-2023 14:15
#9

Thank you, shouldn't at least the top left one be chalybata? geniculata should have dark legs shouldn't it?

Posted by Zeegers on 13-11-2023 21:04
#10

OK, so 2 = morrissi no doubt, 1 seems to be chalybata, but still the antenna seems too long (better pic might help / are you very sure it is the same specimen ?)
3 is challinging. It is neither of two above nor fuscipes. According to Rozkosny in Fauna Entomologica Scandinavica, you don't have geniculata and he mentions that the vertex in nigra (as strobli) is slightly narrower than in chalybata. If you check the hind legs, there are indications of dark rings. So, I am still a bit confused, but that is what is should be, I guess.

Check the leg colouration for yourself, I'd say.

Theo

Posted by MorganA on 14-11-2023 16:39
#11

Thank you, good we agree on #2. Yes #1 is the same specimen, I also add a better picture of the antenna of #1. When it comes to #3 the indication of dark ring that might be on the picture of hind leg must be due to lightning. Hind tibia and femur is clearly completly yellow when looking at them in microscope. So that one remains a challenge..

Posted by Zeegers on 18-11-2023 10:42
#12

but your vertex is much broader in this pic than in your original number 3. Ot at least, so it seems. This last pic with totally yellow legs equals chalybata without any difficulty, I’d say

Theo

Posted by MorganA on 18-11-2023 16:44
#13

Thank you, yes this is the #1 the one i thought was chalybata. so then that one is setteled as well. Did you want a better picture of antenna from specimen 3 as well?

Posted by MorganA on 22-11-2023 19:39
#14

Antenna of # 3