What is the origin of the pachuco from the nonfiction book, The Labyrinth of Solitude: Life and Thought in Mexico?

The pachuco originated in the Mexican youth who lived abroad, particularly those who lived in the United States. Those youth had a strong sense of Mexican identity, yet could not fully live that identity because they were in a different country. At the same time, they did not want to return to Mexico. They were caught between two countries, dissatisfied and unfulfilled in both.