32-bit textures and alpha transparency (OpenGL)

I think I'm going insane...

I'm loading bitmaps from a .Theme file. They are 32-bit. But, for some reason, OpenGL draws the transparent portions as black instead of clear. I'm using the BGRA extension, if that helps.


public void LoadTexture(Bitmap name, ref int target)
            {
                  //Debug.WriteLine(file.PixelFormat);                              
                  using(Bitmap bitmap = new Bitmap(name))
                  {
                        bitmap.RotateFlip(RotateFlipType.RotateNoneFlipY);
                        
                        Rectangle rectangle = new Rectangle(0, 0, bitmap.Width,
                              bitmap.Height);
                        BitmapData bitmapData = bitmap.LockBits(rectangle,
                              ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);

                        
                              
                        Gl.glGenTextures(1, out target);
                        Gl.glBindTexture(Gl.GL_TEXTURE_2D, target);
                        Gl.glTexParameteri(Gl.GL_TEXTURE_2D,
                              Gl.GL_TEXTURE_MAG_FILTER, Gl.GL_LINEAR);
                        Gl.glTexParameteri(Gl.GL_TEXTURE_2D,
                              Gl.GL_TEXTURE_MIN_FILTER, Gl.GL_LINEAR);
                        Glu.gluBuild2DMipmaps(Gl.GL_TEXTURE_2D, 3,
                              bitmapData.Width, bitmapData.Height,
                              Gl.GL_BGRA_EXT, Gl.GL_UNSIGNED_BYTE,
                              bitmapData.Scan0);
                        bitmap.UnlockBits(bitmapData);
                        
                              

                  }
            }

Any ideas why it displays as black?