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Message: <blockquote data-quote="Gavia_immer" data-source="post: 1503055" data-attributes="member: 65934">Chapter 1, 2nd part: fem Common Blue or Brown Argus?This is the big dilemma. But it isn't so difficult as long as you have a decent view of the underwing. Brown Argus has a distinctive double offset spots on the hindwing  that Common Blue doesn't have. This is the best ID tip. Also, Brown Argus doesn't have the cell spot that Common Blue has. But the upperwing also is quite distinctive: Brown Argus is plain brown with well defined orange spots on the edge of the wings. It also have very chequered fringes. In female Common Blue the orange spots fade towards the upper edge of the forewing. The classical female Common blue has blue scales on the upperwing, more or less extensive that Brown Argus doesn't have.Fellow member Jeff has posted a very interesting pic of a fem Common Blue with no blue scales<a href="http://www.birdforum.net/attachment.php?attachmentid=199831&d=1243790853" target="_blank">fem Common Blue by Jeff</a>but as other fellow member (Andrew Gibson) very well pointed out, the fading orange spots gives away it is a female Common Blue. Andrew also mentions that 'the orange spots on the hind wing have a small white edge to them'. I never realized this, but it seems to work in many of the pics I checked. Thanks for that ID tip, Andrew!:t:Next chapter: The Holly Blue.</blockquote>