Yes each side of the vent. Not the middle. The Hemipenes ( male ) are inverted down each side of the tail from each side of the vent. This is what you are looking for. When the Hemipenes are inverted they create very deep tubes which allow the probe to slide freely much deeper than if it was a female. If the probe only freely goes a few scales deep then it is a female. If it goes many then it is a male. I have had males go from 8 all the way to 14 scales. Females usually 5 or 6 max.