I know that. The small town I grew up in that was full of migrant Okies and Arkies is now 99% Hispanic. All the small towns surrounding Bakersfield are.
They're just Mexicans. They aren't a mixture of South and Central American ethnicities; all the others are about 5% of the total.
Just Mexicans, doing the parasite play they did to the Toltecs and the Spaniards: living on the fringes, surviving on scraps, waiting for the day they can overrun and collapse the better civilizations they simply can't conceive of or create.
And they don’t even try to assimilate.
... except for the arabs running the convenience store on the highway... :)