Prickly Pear Borer

Subject:  Unknown bug
Geographic location of the bug:  Southern California
Date: 11/08/2018
Time: 04:21 PM EDT
Your letter to the bugman:  Hi, my family found a blue and white striped caterpillar and this website is the only place that jas a picture of it we would love your help.
How you want your letter signed:  Thank you for your time and consideration, Emily Quick

Dear Emily,
This Caterpillar looks familiar to us, and we suspect we have previously identified it somewhere in our archives.  It reminds us of a Carpenter Moth Caterpillar in the family Cossidae, but we cannot substantiate that suspicion at this time.  Perhaps one of our readers will be able to assist in this identification.

Update:  November 21, 2018
Thanks to a comment from Karl, we have identified this Prickly Pear Borer.  According to BugGuide other common names include:  “banded cactus borers (larvae of junctolineella and subumbrella) and blue cactus borers (larvae of dentata and prodenialis).”