Giant Ichneumon Coloring
Found these terrifying gentle giants in my backyard today. I was wondering what the difference is between the beautiful yellow-auburn colored ones and the shiny black one. There was only one shiny black one that I could see and it was the only one flying around the tree. All the rest were hanging out, depositing their eggs. Thanks!
Your photo shows two species from the genus Megarhyssa. The black specimen is Megarhyssa atrata, the species typically called the Giant Ichneumon. The brown specimen is probably Megarhyssa macrurus.