oceanlis2000's picture

Hoverfly Eristalis but unknown species

Observed: 10th July 2007 By: oceanlis2000oceanlis2000’s reputation in Invertebratesoceanlis2000’s reputation in Invertebratesoceanlis2000’s reputation in Invertebrates
IMG 7347 (2)
IMG 7349 (2)
IMG 7351 (2)
IMG 7351 (3)
IMG 7351 (4)
IMG 7352 (2)
IMG 7353 (2)
IMG 7354 (2)
Description:
Identifications
Species interactions

No interactions present.

Species with which a hoverfly (Eristalis tenax) interacts

Comments

Martin Harvey's picture

Eristalis

I tend to agree with dshubble that Eristalis tenax is the most likely, but difficult to be absolutely sure of this (incidentally, I think some of the remarks above about the pale tibia actually refer to the tarsi!). These large and common hoverflies can be frustrating to identify from photos. Good clear close-ups of the legs, espcially the front legs, and the face are helpful, although won't necessarily solve all the ID puzzles in this genus.

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Entomologist and biological recorder

dshubble's picture

Eristalis

I agree - hard to i.d. by photo (handy that iSpot has a 'probably' category), and yes, you spotted the typo - for 'front tibia', read 'front tarsi'...

oceanlis2000's picture

Hoverfly Eristalis but unknown species

Ok

Is this right

Front leg- tibia yellow, tarsus black
Hind leg tibia all black (not pertinax which is yellow and black)

Are there any other Eristalis species that have all black tibia on the hind leg?

Thanks

Martin Harvey's picture

hind tibia

Re: "Are there any other Eristalis species that have all black tibia on the hind leg?", that's an interesting question! The hind tibia isn't used in the keys for this genus, but in the text of Alan Stubb's book on hoverflies he does say that the "almost completely dark" hind tibia does distinguish E. tenax from the other two large Eristalis, i.e. E. pertinax and E. similis. I'm not absolutely certain whether any of the smaller Eristalis have a dark hind tibia, but the ones I have specimens for do not.

Even if it only works for the larger species this is a good clue for picking out E. tenax, thanks for the reminder! The only note of caution I would add is that the leg colours can be difficult to pick out from a photo, the balance of sun and shade can make them appear lighter or darker than they really are. If possible get photos from more than one angle, as has been done for this observation.

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Entomologist and biological recorder