Swallowtail Larva - Papilio multicaudata

My first thought was early instar Eastern Tiger

if this is the position you found it in - they sit on a silken pad in top of the leaf, unlike other bird-dropping mimics. See discussion on this one:

According to BMNA you are too far west for that one - but maybe Western Tiger has the same behavior? Do you also get Pale Swallowtails in your area (range map here seems to suggest otherwise)? Apparently the caterpillars are very similar - see discussion on this one:

If you can identify the host plant, that might help.

… Hannah Nendick-Mason, 29 August, 2006 - 9:19am

Two-tailed Swallowtail

I sent this also to Bruce Walsh at U of Arizona and he has unequivocally ID'd it as Two-tailed, our state butterfly! Ho hum, back to school...!

… David Bygott, 12 September, 2006 - 10:41am

That's great you got an ID

- and another look-alike to add to the growing list! First one for the guide - I've moved it to the species page.

… Hannah Nendick-Mason, 12 September, 2006 - 1:19pm

Response to Hannah

Thanks for interesting comments. It was indeed attached to a silk pad on top of the leaf of its unknown host bush. It was quite large for a bird-dropping mimic, I was surprised by that.
Western is recorded here, Pale not. Someone suggested Broad Banded, is that possible?
Guess I'll have to go back and find one to rear!

… David Bygott, 30 August, 2006 - 1:00am

I don't know what P. astyalus (Broad-banded) looks like

- there doesn't seem to be a picture of the larva on the web - but it feeds on citrus (this doesn't look like a citrus leaf to me, but I may be wrong). The Western Tiger hosts on a range of other woody plants - though I just noticed our info page says it rests in a shelter, not out in the open. Looks like you might have to raise this one to solve the mystery!

… Hannah Nendick-Mason, 30 August, 2006 - 6:12am