A while back, I was wondering about scorpions and their legs. The assumption is that they have six legs, and knowing that they are arachnids, I assumed that the pincers at were, intact, modified legs. However, whenever I’ve seen a scorpion, it has eight legs AND the pincers. So, where are the pincers from? They are pedipalps -
http://en.wikipedia.org/wiki/Pedipalp - developments of antennae (genetic studies reveal this to be the most likely origin).
So mistaking the pincers for legs is, I guess, an easy mistake to make if you aren‘t looking carefully enough.