Posted by Alvesgaspar on 23-11-2007 23:57
#1
I'm having some trouble in the identification of the Eristlis species, namely E. tenax, E. pertinax and E. arbustorum. The gallery doesn't help much as the variation inside a species seems sometimes greater than between species. Can I have some expert help for the future? I attach three pictures which I I have identified all as E. tenax. But are they really?
Posted by Sundew on 24-11-2007 00:43
#4
You are not alone with the
Eristalis problem. There are still much more species in Europe, and the females look different from the males, so one can get rather confused. There was a good
Eristalis key in the internet that has been removed meanwhile; however, I made a copy :D. I'll send it to you as an e-mail attachment, ok?
Your three
Eristalis have all dark feet, so no
E. pertinax. E. tenax has two bands of hair on each eye that are said to be distinct, but I photographed the fly very often and rarely can recognize these bands. - Your middle one has a clearly feathery arista, that's not typical for
E. tenax.
E. arbustorum is smaller than the two other species, tibia 2 has a black top quarter.
So that's my knowledge up to now, and I share it willingly. Much luck with
Eristalis, it's such a nice syrphid!
Sundew