Diptera.info

Posted by blowave on 22-09-2011 17:07

Hello!

This should be Eristalis arbustorum but it looks more like E. interrupta except the stigma is too long. The face doesn't seem to fit arbustorum, but I didn't get a frontal shot. Could it be anything else? It's driving me crazy. :S

Two shots only from which I have made closer crops.

18th July, my garden on Achillea, near Lincoln UK.

Janet

Posted by Sundew on 22-09-2011 20:32

According to the Eristalis key (http://web.archiv...html#item8), E. abusivus has a short-haired arista and is thus out of the question. I could live with E. arbustorum...

Edited by Sundew on 22-09-2011 20:33

Posted by blowave on 22-09-2011 21:38

Sundew wrote:
According to the Eristalis key (http://web.archiv...html#item8), E. abusivus has a short-haired arista and is thus out of the question. I could live with E. arbustorum...

The link doesn't give the key but I have those anyway. I bought the book too, the first couplet which leads to abusiva states hairs shorter than twice the diameter of arista base or bare. The other option states hairs much longer than twice the diameter of arista. I'm not sure which this fits into, the hairs do appear to be longer but I wouldn't say much longer and photos don't always show the reality.

I have looked at other keys but still can't decide! If I follow the Syrph the Net keys using the option of arista hairs no more than 2x diameter it leads to abusiva, some alternative options en route are not in the UK or are obviously not appropriate. The other option is arista hairs more than 3x diameter.

Posted by blowave on 22-09-2011 22:02

#10

Thanks nielsyese! I had another fly shortly before this one, about 5-6 minutes apart. At first I thought it was the same fly but I wasn't sure, it didn't appear to have so much hair on the abdomen from the side view but I could see T2 had hairs. Apart from that they looked the same. both equally pregnant etc. but there looks to be a bare stripe on the face of the other fly.

I'm not over sure what that is either, the stigma looks squarish but is quite large. I know I should post it separately but as they are suspiciously the same I'll post it here..

Posted by Pierre-Yves on 22-09-2011 22:32

#12

Hello everybodies :)

For the two last pictures, the first is a female of E. pertinax with this yellow tarsa on the first and second legs, the second is again a female of E. arbustorum.

P-Y

Posted by blowave on 22-09-2011 22:42

#13

Pierre-Yves wrote:
Hello everybodies :)

For the two last pictures, the first is a female of E. pertinax with this yellow tarsa on the first and second legs, the second is again a female of E. arbustorum.

P-Y

Hello Pierre.

The last two photos are of the same fly. ;)

Posted by Sundew on 22-09-2011 23:12

#14

Here the arista seems to be much shorter-haired - hmmm.... Eristalis is difficult. I'd like to hear the opinion of St�phane Lebrun.
BTW, the link to the key works well if one is patient enough to wait for loading ;).

Edited by Sundew on 22-09-2011 23:14

Posted by blowave on 23-09-2011 02:42

#15

Most Eristalis I have had are not so difficult as these! ;)

Lol, I looked at the link again and even though the bar at the bottom said 'done' there was an "Impatient" link which brought the key up! :P

Posted by nielsyese on 23-09-2011 11:27

#16

The first picture of the last two is very misleading in colour, but it is E. arbustorum again. The arista of E. abusiva is nearly bald. Look here for an example of E. abusiva http://waarneming...w/47803943
Regards,
Niels

Posted by blowave on 23-09-2011 15:40

#17

Thank you Niels, that does show the arista to be nearly bald. What do you think to the apparent bare stripe on the face which is showing in the first of the last two photos?