Hello,
The top one I'm pretty sure is a female, but the bottom one I'm not sure about. If I had to guess I would say its a female. Male Peppered Cories have a longer more pointed dorsal fin then the females. By the way, I'm pretty sure that your Julii is a Three-Striped Corydoras. I bought some so called Juliis from the petstore, but when I got them home I realized they were Three-Striped Cordoras(Corydoras Trilineatus). When you see the so called Juliis for sale, theres a 95% percent chance that they are the Three-Striped!
Cory Lover