[Arid_gardener] Question from Home-Hort WWW page

[linpitz at aol.com]

Linda Pitzer
85361
linpitz at aol.com

We are being "invaded" by a LOT of plump yellow with 2 black lines going the entire lenght of a caterpillar that are from 1" to 3+" long.
We live in the desert West of Wittmann.
What kind are they?
What do they morf into?
Any way to control/exterminate them?
We look forward to a response....thanks