GUI.DrawTexture not working? (nothing shows up)

I have the following code attached to my main camera:

    using UnityEngine;
    using System.Collections;
    public class DrawGui : MonoBehaviour {
    	public Texture crosshair;
    	// Use this for initialization
    	void Start () {
    	// Update is called once per frame
    	void Update () {
    	void onGUI(){
    		//draw crosshairs
    		//GUI.DrawTexture(new Rect((Screen.width/2) - 3, (Screen.height/2) - 3, (Screen.width/2) + 3, (Screen.height/2) + 3),crosshair);
    		GUI.DrawTexture (new Rect(10,10,60,60), crosshair, ScaleMode.ScaleToFit);

The image I’m trying to use for the GUI is just a small red square (as a .png file) and is inserted into the crosshair variable in the inspector.

The problem: It’s not showing up! I can’t seem to get the red square to appear on the screen at all. I’ve tried changing the values in the rect and everything. Anyone know what’s up?

The language is case sensitive. The function name is ‘OnGUI()’ with an upper case ‘o’.