Achemon Sphinx Caterpillar

Subject:  Beach bug
Geographic location of the bug:  Cape cod ocean beach
Date: 07/29/2018
Time: 03:07 PM EDT
Your letter to the bugman:  What is this crazy thing?
How you want your letter signed:  Keyes fam

Achemon Sphinx Caterpillar

Dear Keyes fam,
We especially love your aerial or dorsal view of this Achemon Sphinx Caterpillar because it shows how effectively the caudal bump resembles an eye, making this harmless caterpillar take on the appearance of a threatening snake, at least to birds or other predators that might find this fat, mature caterpillar to be a toothsome feast.  According to Sphingidae of the Americas:  “Immature larvae have the characteristic horn-like tail which drops off (i.e., does not develop) after the fourth instar.  Feeding lasts for three to four weeks and full grown larvae leave the host to pupate in undeground [sic] burrows.”  The big mystery to us is how it ended up on the beach.  Perhaps a nearby garden is growing grapes or another preferred food plant and it left the plant to pupate, when it was snatched by a bird that began to carry it over the sand.  The caterpillar then thrashed about and perhaps the false eye startled the bird and it dropped dinner in the dunes.

Achemon Sphinx Caterpillar
This is great! Thank you very much. We were surprised by the size, color, and that it was on the beach. Our theory was also that a bird may have dropped it there. We appreciate your help with the identification!
Oh, we have another question. What are the white squiggly things that run the length on each side? And do they serve a purpose? Thank you!!!!!
The markings on the side may help camouflage the caterpillar while it is feeding in dappled light.

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