What's That Bug? does not endorse extermination

Subject:  Red Caterpillar
Geographic location of the bug:  Denver Colorado
Date: 09/17/2018
Time: 05:30 PM EDT
Your letter to the bugman:  Any idea what kind of bug this is? I’m 99% sure it is a caterpillar, but can’t find a similar one online. It is definitely a creature of some sort, it moved when I tried to pick it up.
How you want your letter signed:  Robin

Achemon Sphinx Caterpillar

Dear Robin,
This is a third instar Pandorus Sphinx Caterpillar, and here is a matching image from BugGuide.  According to Sphingidae of the Americas:  “L3: At this stage, the larvae look quite different. The long straight horn now curves and looks strikingly similar to a
Parthenocissus quinquefolia tendril. The larvae can be yellowish, green, brownish or reddish with 5 white eyespots around the spiracles on the sides of the larvae.”  Your individual has not yet shed its caudal horn.

Correction:  Achemon Sphinx Caterpillar
Thanks to a correction from frequent WTB? contributor Bostjan Dvorak, we acknowledge our initial mistake.


What's That Bug? does not endorse extermination
Location: Denver, Colorado

3 Responses to Achemon Sphinx Caterpillar

  1. Bostjan Dvorak says:

    This pretty caterpillar is one of Eumorpha achemon I suppose; the white lateral ornaments are multilayered, more complex than in E. pandorus, and it is completely covered by little spots.

    Best wishes

  2. Bostjan Dvorak says:

    One more distinctive characteristic I forgot to mention yesterday: there are six pairs of lateral ornaments in this species’ caterpillar (Eumorpha achemon, as pictured on the photo) instead of five (E. pandorus); and the latter one might rather be restricted to the eastern parts of the continent, but I am not sure whether it could be spread to the western areas as synanthropic species in the meantime… They cooccur in the eastern half of the territory. – A fascinating genus of hawkmoths with the larvae pupating in underground chambers, which is typical for many Sphinginae, but quite unusual for the Macroglossinae…

    Nice wishes from Berlin

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