This is a post I made on another forum, the Crab Street Journal, about telling the difference between an E and a ruggie:
The way to tell an E from a ruggie is Es have thicker legs and eyestalks than ruggies. E eyestalks are fat and candy corn shaped, ruggie eyes are thinner. Ruggies will also have a dark smudge under their eyes.
E eyes:
Ruggie eyes:
Es tend to be a dark brown or bluish color and have pinstriping on their legs, which get darker at the tips. Ruggies can be any color and may have pinstriping on their legs, but it gets lighter toward the tips not darker. Ruggies also have a distinct second plate on their shield leg (2nd walking leg from left). They are the only species that has this extra plate and it gives their shield leg a 'twisted' appearance.
E legs:
Ruggie legs, notice the double plate on the last walking leg on the left:
Es antannae are all brown, ruggie inner antannae are often red or orange on the inside pair.
E antannae:
Ruggie red inner antannae:
E big pinchers have very light stitch marks and tend to be mono-colored. And they will often cross their legs when in their shell. Ruggie bps have pronounced stitch marks /////, often have a very light stripe, and they only cross their legs if their shell is way too small.
E BP:
Ruggie BP:
Hope that helps! It took me a long time to tell the difference between the two as well. When I first got my 4 ruggies, I confused them with Es and so spent that weekend looking at hundreds of pictures and studying the differences.
