Posted by
lagura on 05-10-2009 23:17
#1
I don't seem to be able to figure the Eristalis' out. Lovely flies but oh so variable.
These three was photographed the same day and roughly at the same place. I believe the first two to female and male E. pertinax and the third to be a female E. tenax. But I wouldn't be surprised if it was the other way around
Size: ~14mm
Date: 7 September 2009
Location: On raspberry leaves on a small meadow (Helsingborg, Sweden)
Thanks!
Here's the first female
Posted by
Andre on 06-10-2009 10:54
#4
It's the other way round
Eristalis pertinax is the only species with all yellow front and middle tarsae.
Also, look carefully at the color of the spots on the abdomen. In
pertinax they can be very faint to very clear, but the color is always yellowish. In
tenax they can also be very faint (to absent) to very clear, but the color always tends to be reddish.
From these pics the two vertical 'bands' of hairs over the eyes of
tenax are not clearly visible, but that can be a very useful character too.
The stigma on the wing of
pertinax, as you see very clear here, is usually quite long, whereas in
tenax it is usually about half that length.
