The first wasp had come back! But not empty handed, or rather not empty mouthed, for in her pointed jaws she held a limp measuring-worm about an inch and a quarter long. A measuring-worm or looper is the caterpillar of a certain kind of moth, and it loops or measures when it walks because it has no feet on the middle of the under side of the body as other caterpillars have, and so has to draw its tail pretty nearly up its head to take a step forward. This naturally makes its body rise up in a fold or loop. "See," cried Mary, "the wasp is going to put the measuring-worm into the hole." That is exactly what happened. How the wasp could tell where the hole was, was surprising, for it had so carefully put the bit of salt crust in place that you couldn't tell the top of the hole from the rest of the crust-covered ground. But our wasp came straight to the right place. Perhaps as a carrier-pigeon comes to its loft from a hundred miles away, or a cat carried away in a bag to a strange place finds its way quickly back home. Some of the other wasps that we watched later weren't so sure of their holes, though, and other people who have watched digger-wasps in other places have found them showing varying degrees of uncertainty about locating their nests. Mr. and Mrs. Peckham, who have studied the behavior of the various kinds of digger-wasps more than anybody else in this country, have concluded that the wasps "are guided in their movements by their memory of localities. They go from place to place quite readily because they are familiar with the details of the landscape in the district they inhabit. Fair eyesight and a moderately good memory on their part are all that need be assumed in this simple explanation of the problem." But quite different from this conclusion is that of Fabre, the wonderful French observer of wasps, who experimented on them in regard to this matter of finding and knowing their holes, by carrying them away shut up in a dark box to the center of a village three kilometers from the nesting ground, and releasing them after being kept all night in the dark boxes. These wasps when released in the busy town, certainly a place never visited by them before, immediately mounted vertically to above the roofs and then instantly and energetically flew south, which was the direction of their holes. Nine separate wasps released one at a time did this without a moment's hesitation, and the next day Fabre found them all at work again at their hole-digging. He knew them by two spots of white paint he had put on each one.