At first I thought this was mating behavior but after doing some homework I believe these are two different female giant ichneumon wasps laying eggs at the same time. Megarhyssa macrurus, also known as the long-tailed giant ichneumon wasp and Megarhyssa atrata, also known as the black giant ichneumon wasp. Because their egg laying ovipositor is much too long to drill into the wood at the correct angle, the giant ichneumon wasp is equipped with a special flexible pouch they can curl up the ovipositor into until the angle is just right to start drilling into the wood.
