Ichneumon Wasps

These wasps were what it seems detecting larvae in the bark of a dead tree and ovipositing their eggs on them (as they are parasitic).

Ichneumon wasps differ from typical, aculeate wasps, which sting in defense and do not pass their eggs along the stinger, in that the antennae have more segments; typically 16 or more, whereas the others have 13 or fewer. Female ichneumon wasps sometimes have an ovipositor longer than their body. Ovipositors and stingers are homologous structures; Ichneumons generally inject venom along with the egg, but only larger species, with relatively shorter ovipositors, use the ovipositor as a stinger in defense.