This large wasp may look fierce because of her size and that long ovipositor. But these wasps cannot sting!! What looks like a stinger is the ovipositor which she uses to lay eggs. If you are someone who likes a green lawn, you should probably welcome them if you see them around your garden because they prey on the June beetle larvae that cause the brown patches on your lawn. Bug Guide has this to say: "Female thrusts ovipositor into soil to detect host, lays one egg on each. Pelecinid larva burrows into the beetle larva, killing it. Wasp larva scavenges remains and pupates there in soil."