Is this Ischnura perparva? - Ischnura cervula

Moved

Moved from Forktails. We received an email identifying this image as cervula and will move it there.
Comment received: "The Ischnura I would say without much doubt is I. cervula. I think enough of the color pattern is visible to eliminate I. perparva, which develops much paler pruinosity than cervula."

… john and jane balaban, 24 February, 2011 - 7:06pm

Thanks J & J for the move...

... and also thanks to whomever the "mystery" person was who offered their identification help via e-mail. :-)

… Harsi S. Parker, 24 February, 2011 - 8:06pm

ID - Mystery Person

I sent your image to Dennis Paulson. The comments are his.

… William Edwards, 25 February, 2011 - 7:24pm

Excellent! Looks like your initial ID was good from the start!

William, thank you so much, for soliciting Dennis' help in positively identifying this one. I'm a big fan of his book and very much appreciate his assistance.

… Harsi S. Parker, 25 February, 2011 - 10:50pm

Moved

Moved from Damselflies.

PLEASE NOTE: I've frassed the detail images of the prothorax that are referenced in this post, as they did not prove useful in obtaining a further ID. I've moved this image to the genus page primarily because I think the comments left by William may be of interest to others attempting to discern the differences between female I. perparva and I. cervula. If anyone feels this image is better placed in Frass -- I certainly have no objections.

… Harsi S. Parker, 28 April, 2010 - 11:50am

Looks like - Ischnura cervula (female)

See Don Roberson - Pacific Forktail Photos and note the large photo of older female at the bottom.

See also Don Roberson - Western Forktail Photos and note his excellent discussions on how to separate these two species.

If you could make an enlargement of the prothorax (the area just behind the head and in front of the thorax) it might be possible to definitively identify this damselfly.

… William Edwards, 18 April, 2010 - 12:03pm

Cervula vs. perparva

Hello, William. Thanks so much for trying to help me out with an ID on this one! The webpages you referenced are indeed a wonderful reference and I have also been trying to glean clues from my copy of Dennis Paulson's excellent book. I have gone ahead and uploaded another image showing a few cropped views of the thorax, but I'm not feeling very hopeful that either one shows enough prothorax detail (or the right angle) to be of much use to you. Unfortunately, it was very bright and sunny and this damsel didn't sit still long enough for me to get the shots I wanted... I will certainly try again in the same area and perhaps can come up with some more definitive images.

… Harsi S. Parker, 18 April, 2010 - 1:57pm

Ischnura cervula - Prothorax

Thank you for posting these images. Unfortunately I can't or don't have the experience to see the parts that I'm looking for.
John Abbott in (1) states in his key to FEMALE Ischnura:
Hind margin of prothorax with tongue-like median lobe bearing a tuft of long setae on either side (Pacific Forktail)

This is illustrated on page 115 of Paulson (2)

… William Edwards, 18 April, 2010 - 2:42pm