All of a sudden, while Mary and I were smiling at this too early bird of a tarantula, he went up on his hind legs in fighting attitude, and at the same instant down darted a great tarantula hawk, that is, a Pepsis wasp. Her armored body glinted cool and metallic in the red sunset light, and her great wings had a suggestive shining of dull fire about them. She checked her swoop just before reaching Eurypelma, and made a quick dart over him, and then a quick turn back, intending to catch the tarantula in the rear. But lethargic and owly as Eurypelma had been a moment before, he was now all alertness and agility. He had to be. He was defending his life. One full fair stab of the poisoned javelin, sheathed but ready at the tip of the flexible, blue-black body hovering over him, and it would be over with Eurypelma. And he knew it. Or perhaps he didn't. But he acted as if he did. He was going to do his best not to be stabbed; that was sure. And Pepsis was going to do her best to stab; that also was quickly certain. At the same time Pepsis knew--or anyway acted as if she did--that to be struck by one or both of those terrible vertical, poison-filled fangs was sure death. It would be like a blow from a battle-axe, with the added horror of mortal poison poured into the wound. So Eurypelma about-faced like a flash, and Pepsis was foiled in her strategy. She flew up and a yard away, then returned to the attack. She flew about in swift circles over his head, preparatory to darting in again. But Eurypelma was ready. As she swooped viciously down, he lunged up and forward with a half-leap, half-forward fall, and came within an ace of striking the trailing blue-black abdomen with his reaching fangs. Indeed it seemed to Mary and me as if they really grazed the metallic body. But evidently they had not pierced the smooth armor. Nor had Pepsis in that breathless moment of close quarters been able to plant her lance. She whirled up, high this time but immediately back, although a little more wary evidently, for she checked her downward plunge three or four inches from the dancing champion on the ground. And so for wild minute after minute it went on; Eurypelma always up and tip-toeing on those strong hind legs, with open, armed mouth always toward the point of attack, and Pepsis ever darting down, up, over, across, and in and out in dizzy dashes, but never quite closing.