Santana introduces me to two of the younger musicians: Miguel Barron, who plays violin, and Moises Trujillo, whose instrument is the vihuela, reminiscent of a ukelele. Though both are only in their early twenties, they began their musical apprenticeships more than a decade ago under the auspices of older relatives. ''There have been mariachis in my family for generations,'' says Barron, dusting off his costume, which is maroon with silver rooster bangles sewn along the pant legs. ''As a kid, I would watch my uncles play and think, This is the only thing I ever want to do.'' The downside of being a mariachi, adds Trujillo, is that ''Charros and mariachis have a terrible image. We're supposed to be macho skirt chasers and violent drunks. And that hurts, because a lot of us are religious, family types.'' And mariachis work long hours: While their usual schedule is from dusk to midnight, they're often called out of bed on short notice to sing amends beneath the balconies of peeved wives and girlfriends at dawn.