Thoas Swallowtail - Papilio cresphontes

Moved

Moved from Butterflies (excluding skippers).

… David J. Ferguson, 1 October, 2009 - 5:31pm

Moved

… john and jane balaban, 6 September, 2009 - 9:53am

Hi all

It's definitely a Giant. If you search a little here on BugGuide, there are some discussions about telling the difference, but I don't remember exactly where they are hiding. The two do look different, but it's a subtle distinction. I never thought them difficult to tell apart, as long as you have some good views, but others can't seem to see it. The reason this one looks dark from below is the back lighting, which causes the dark color above to show through and obscure the actual yellow color below. This one looks like probably a male, but it's hard to see enough detail of the abdomen to be certain.

I haven't seen one in my yard in central New Mexico for a few years, perhaps they'll be back this year. I should check the Rue plants for caterpillars!

Taste test - mmm - Giants feed on Rutaceae, and Thoas apparently on Piperaceae, so there might just be something to this :0)

… David J. Ferguson, 13 August, 2009 - 5:58pm

I would suggest...

Cropping the first and last image...

Or email the full size images to me and I can crop them and replace your current images. It really helps to have as much butterfly and the least amount of background in each image.

… Ron M., 13 August, 2009 - 3:11pm

Very Likely - Papilio cresphontes

Giant Swallowtail

See Article on how to separate the Giant
from Thoas Swallowtail.

… William Edwards, 13 August, 2009 - 1:40pm

Giant Swallowtail/Thoas Swallowtail

I thought so as well originally, but my guide shows the giant as mostly yellow underparts, and this one is black with yellow spots in a line at the top and bottom on the underparts.

… Douglas, 13 August, 2009 - 2:32pm

Giant Swallowtail

Here's another photo of a Giant Swallowtail that appears similar to yours.

Here are some PHOTOS of Thoas Swallowtails.
I don't know what the significance of the different color of the underside is.
The diagnostic characteristics are on the upperside according to what I've read.

… William Edwards, 13 August, 2009 - 3:28pm

Thoas vs. Giant Swallowtail

I do believe you are right as to this burrterfly being a Giant vs. a Thoas. Either way it has been a pure joy to see in my backyard. I am really inexpeienced at identifying butterflies, as my original interest has been briding. I started taking notes of butterflies that I saw in the field while birding. As a side note, I have a Pipevine Swallowtail in the back yard as well, a few Monarchs and Queens, an occasional Arizona Sister, and a few small yellow and whites that I believe to be a variety of sulphers (they are to quick for me to identify).

I think my next step will be to catch it and identify it by taste. Does anyone know the differance in taste between the Thoas and the Giant? (Just Kidding.)

… Douglas, 13 August, 2009 - 4:18pm

If you perform the taste test...

...prefered preparation is none (raw) or lightly microwaved. Using commercially available Swallowtail Helper will adversely affect your results by masking the natural flavor.

… Ron Hemberger, 13 August, 2009 - 5:03pm