Adding labels iteratively to Tkinter form

I am trying to iteratively add fields to a Tkinter form by looping through a list. The form generates with no errors, but the labels are not present. What is going on here?

from Tkinter import *
class User_Input:

    def __init__(self, parent):
        fields = ['Text Box 1', 'Text Box 2']
        GUIFrame =Frame(parent, width=300, height=200)
        GUIFrame.pack(expand=False, anchor=CENTER)
        field_index = 10
        for field in fields:
            self.field = Entry(text=field)
            self.field.place(x=65, y = field_index)
            field_index += 25

        self.Button2 = Button(parent, text='exit', command= parent.quit)
        self.Button2.place(x=160, y=60)

root = Tk()
MainFrame =User_Input(root)

root.mainloop()