Posted by Nikita Vikhrev on 16-07-2006 18:33
#1
Today after an hour of regarding at my collected Hybomitras I was deeply demoralized.
I think that this one is most probably H. bimaculata, but honetly it is rather speculation than real understanding how to distinguish species inside this genus.
Posted by Tony Irwin on 16-07-2006 22:41
#2
Hi Nikita
No Need to be demoralised - this is a tough group, and not every fly will be straightforward! :@ - And there's nothing wrong with speculation! Remember that identifying flies is more of an art than a science. :D
My feeling is that this is Hybomitra distinguenda.
There's not much between a pale bimaculata and distinguenda, but bimaculata tends to have black cheek hairs and a black second antennal segment. WIth its pale cheek hairs and brown second antennal segment, your specimen is more like distinguenda.
H.bimaculata has longer hairs on the anterior face of the mid tibia as well, but it may be best (if you have the specimen) to examine the shape of sternite 8. The differences between the species are perhaps not as great as some drawings indicate, but they are consistent and very useful when you get used to them. If you have more typical specimens of the "problem species" then you have the ideal reference material!:)
Posted by Nikita Vikhrev on 17-07-2006 09:34
#3
Thank you Tony.
In Moscow Zoological Musem there are very rich collection of Tabanidae, it seems that I have to spend a day here.
Nikita