on the purslane, and most of all on the bean-plants.  These were examined carefully, the wasp going up and down the stems and looking under every leaf, but the search was so frequently unsuccessful that in estimating their work we are inclined to think that they can scarcely average one caterpillar a day.  When they were hunting over bare ground they often paused and seemed to listen, and in the beginning we expected to see them burrow down and drag a victim from under the soil, but this never happened.

In this species, as in every one that we have studied, we have a most interesting variation among the different individuals, not only in methods but in character and intellect.  While one was beguiled from her hunting by every sorrel blossom she passed, another stuck to her work with indefatigable perseverance.  While one stung her caterpillar so carelessly and made her nest in so shiftless a way that her young could only survive through some lucky chance, another devoted herself to these duties, not only with conscientious thoroughness, but with an apparent craving after artistic perfection that was touching to see.

The method employed by the Ammophilae in stinging their prey is more complex than that of any other predatory wasp.  The larvae with which they provision their nests are made up of thirteen segments, and each of these has its own nervous centre or ganglion.  Hence if the caterpillar is to be reduced to a state of immobility, or to state so nearly approaching immobility that the egg may be safely laid upon it, a single sting, such as is given by some of the Pompilidae to their captured spiders, will be scarcely sufficient.  All this we knew from Fabre’s “Souvenirs,” and yet we were not at all prepared to believe that any plain American wasp could supply us with such a thrilling performance as that of the Gallic hirsuta, which he so dramatically describes.  We were, however, most anxious to be present at the all-important moment that we might see for ourselves just how and where Ammophila urnaria stings her victim.

For a whole week of scorching summer weather we lived in the bean patch, scorning fatigue.  We quoted to each other the example of Fabre’s daughter Claire, whose determination to solve the problem of Odynerus led to a sun-stroke.  We followed scores of wasps as they hunted; we ran, we threw ourselves upon the ground, we scrambled along on our hands and knees in our desperate endeavors to keep them in view, and yet they escaped us.  After we had kept one in sight for an hour or more some sudden flight would carry her far away and all our labor was lost.

At last, however, our day came.  We were doing a little hunting on our own account, hoping to find some larvae which we could drop in view of the wasps and thus lead them to display their powers, when we saw an urnaria fly up from the ground to the underside of a bean leaf and knock down a small green caterpillar.  Breathless with an excitement which will be understood by those who have tasted the joy of such a moment, we hung over the actors in our little drama.  The ground was bare, we were close by and could see every motion distinctly.  Nothing more perfect could have been desired.