Common blue or Brown argus?

yellowhammer · Post by **yellowhammer** » Tue May 22, 2007 8:00 pm

Hi everyone. I've been reading this thread http://www.ukbutterflies.co.uk/phpBB2/v ... php?t=1134 with the debate over the species of the blue. I took this photo today & I was happy with an ID of female Common Blue, but now you've got me doubting! Any ideas on what it is, or what to look for when I go back, please? Sorry it's a bad picture;

Just to confuse matters, when I saw it I thought it was a brown argus, although I've never seen a BA at this site - lots of blues though...

Trev Sawyer · Post by **Trev Sawyer** » Tue May 22, 2007 8:13 pm

The sheen on the body 'hairs' may look bluish, but it is the scales on the inner wings which would signify a blue, so I'd also say a Brown Argus. Unfortunately, not much help looking at the underwings either.... they seem to be just about identical too! (look forward to a definitive identification by gubberthump too

)

Trev

yellowhammer · Post by **yellowhammer** » Tue May 22, 2007 8:16 pm

Cheers Trev

I have to say though, I was hoping for a long, complicated, technical gubberthump explanation too

Post by **Padfield** » Tue May 22, 2007 8:45 pm

That does look like a brown argus to me.

Things to look out for when you go back are:

The dark discal spot on the upperside forewing of brown argus, which is always well-defined (visible in the picture below).

The chequered fringe of brown argus (visible in fresh specimens).

Absence of a cell spot in the underside forewing of brown argus (visible in the picture below).

The arrangement of the two spots circled in the picture below. The upper picture is a brown argus and the lower a (male) common blue. In brown argus they form a vertical colon, while in common blue they are oblique, in line with the general arc of the spots.

Hope this helps!

Guy

Post by **Padfield** » Tue May 22, 2007 8:54 pm

PS - I forgot to mention that in brown argus the gubberthump has three rings while in common blue there are only two.

Guy

yellowhammer · Post by **yellowhammer** » Tue May 22, 2007 9:04 pm

Wow - thanks Guy. BA it is, and a new species for the site (for me at least). Much appreciated, both of you

Trev Sawyer · Post by **Trev Sawyer** » Wed May 23, 2007 7:31 am

Yes, thanks Guy...
I had looked at the underside of both species a number of times and could not work out any differences at all. These tips make things much more obvious and hopefully Pete will be able to add these little gems to the detailed list with each species at some point (God knows when though, as I'm sure he must be up to his eyeballs with potential additions to the site and I suppose we must allow him to do some butterflying of his own now the sun is out

)

Trev