Thorax, propodeal pit, inner surface appearance
Finely pebbled, coarse, and dull
Note that the propodeal pit is located at the base of the propodeum, just above where the abdomen attaches to the thorax. Because of its location, it will likely be hidden if the abdomen is bent upwards. Also note that you need to look closely sometimes to distinguish between smooth-shiny and dull-finely pebbled. Smooth-shiney is like a mirror with no apparent lines crossing the surface of the feature where as dull-coarse has, at minimum, a series of very fine lines that decreases the surface reflectivity of the segment in question, somewhat similar to a fine leather, light can reflect but not in the same way as a mirror.