Thread subject: Diptera.info :: Volucella zonaria or inanis please

Posted by richard on 14-06-2007 08:35
#1

Hello,

It is many months since I requested some help.

I thought this was a hornet as it flew past because of the size. Taken in South Nottinghamshire last week I have narrowed it down to Volucella zonaria or inanis. The latter have been recorder locally before so that is the most likely id.

I have read somewhere that the colour of the vental abdominal segments (sternites?) are important if making the id. Would someone be able to explain further please?

Thanks

Posted by caliprobola on 14-06-2007 09:30
#2

this is a female Volucella zonaria, sternite 2&3 are largely black. Volucella inanis has sternite 2 completely yellow & st3 yellow in the first part, also inanis is smaller and has a more blackish thorax.

grtz
pieter

Posted by richard on 14-06-2007 10:58
#3

Thank you Pieter

I presume that the first sternite is the one that is virtually all black, he second sternite is the one that is perhaps 1/4 yellow and 3/4 blackand the third sternite is the one with a hint of brown towards the caudal end?

May I ask why this is a female please?

Thanks again

Richard


Posted by caliprobola on 14-06-2007 11:19
#4

no, the sternite are the plates on the underside of the abdomen, the first sternite is small and is impossible to see on this pic. So the second one is the all black one, the 3d one is the one 1/4 yellow and 3/4 black.
It is a female because the eyes are clearly seperated on the top side. Males have the eyes bigger so on the upperside of the head, the eyes reach each other. This is so for the most of the syrphids. Also on this pic you should probably see the asymetric shape of the genitalia on the end of a male abdomen.

grtz
pieter

Posted by richard on 14-06-2007 16:04
#5

Thank you Pieter - much appreciated.

Richard