Huh, odd, doesn't appear to be a gynandromorph after all, looks rather normal ventrally. I don't know what the cause of this mutation is, pretty weird!
If it were a hybrid between regularis and petiveriana/bernhardti, then I don't think the spots would be plain white like that personally. As for a petiveriana x bernhardti cross, that's very unlikely as well, bernhardti are the dominant domino roach in the hobby, I only know of one person in Hong Kong who has a recent import of what may be "real petiveriana", but even then they might actually be defranceschii. So yours are very unlikely to be hybrids, this seems more like some random genetic mutation, maybe a chimera of some sort.I really can't recall... I have this weird recollection of having a domino roach inside the regularis colony and throwing it inside the domino bin... If I am not making up stuff in my mind... it's possible I may have contaminated my colony? Do u think this may be a cross breeding of petiveriana with bearndthardi?