Well, first of all, I think it is incumbent on all of us to learn the Field Marks ourselves; that is probably the best thing…….especially when dealing with more or less difficult to ID species…….A good source of info to study in this regard would be the Butterflies of America website:
and go to INTERACTIVE LIST where you can see and compare good photos of specimens…
But here, in terms of Eastern Comma vs Green Comma – when views of undersides are not available (as was the case in the photos of Gray Commas late last month), a few useful Field Marks are probably as follows:
Green Comma has noticeably more “jagged” and uneven wing margins that Eastern Comma, and also has the orange areas more two-toned between orange and yellow. For example, this can be seen in the submarginal lunules of the FW and the submarginal lighter spots inside the darker border of the HW. The subapical area, between the two dark areas of the FW is also yellow in Green Comma but orange in Eastern Comma. The Eastern Comma – especially the winter form – has prominent violet(-gray) margins that is lacking in the Green Comma. The Green Comma also has more pronounced black markings on the FW and is overall darker than is the Eastern.
Again, and this is the same for Eastern vs Gray Comma: The Green Comma has an overall different “look” to it than the Eastern Comma. And you can also say that each of the more “Northern” Commas – the Gray, Green and Hoary Commas – all have a different “look” to them compared to that of the more “southern” Eastern Comma. And then, each of these three also have different “looks” in comparison to each other.
I mentioned before when we were discussing the Gray Commas, that even the shape (character) of that largest black bar at the end of the FW cell (as well as ALL of the black FW spots) can be important in determining a Gray vs Eastern or Green Comma, and probably also a Hoary Comma. These characters are all part of the overall “look” of a species. As I also mentioned, the character of the large cell-end black bar has at times been useful to me at the Scott Bog in northern NH where that form of the Green Comma female (silvius, I believe it is called) which has a dark brownish-gray underside with essentially no green, in trying to ID this as a Green and not a Gray Comma. So again, one needs to simply LEARN them, I would suggest.
Also, when any of these specimens are more worn (this Green Comma is rather surprisingly in good condition for a hibernator) then the overall “look” becomes even more important as individual Field Marks may be more difficult to determine.
I asked this question earlier -what are those field marks that distinguishes this Green from the Eastern??? HELP!
A couple of whites through the yd today, but neither stopped long enough to get a positive ID. What I did notice in flight were dark edges on the wings??? Would both W VA and Cabbage be flying at this time? No toothwort in sight and open yard. Glimpsed a dark butterfly too - but noooooo ideas on that one!
On 4/18/2016 6:51 PM, Alex Grkovich wrote:
The more that I look at this, the more I believe this to be a Green Comma. Look at the Field Marks.....absolutely not an Eastern Comma.
That actually looks more like a Green Comma (???) at least from above...
A nice surprise and beginning for the season!
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[log in to unmask]" alt="Comma, Eastern #07b, Wildcat Road, Chittenden, VT, 2016-04-18.jpg">
Cheers, Roy Pilcher