Mr. Seth Green, writing to the New York World of May 14, says that one morning when he was watching a spider's nest, a wasp alighted within an inch or two of the nest, on the side opposite the opening. Creeping noiselessly around towards the entrance of the nest the wasp stopped a little short of it, and for a moment remained perfectly quiet; then reaching out one of his antennæ he wriggled it before the opening and withdrew it. This overture had the desired effect, for the boss of the nest, as large a spider as one ordinarily sees, came out to see what was wrong and to set it to rights. No sooner had the spider emerged to that point at which he was at the worst disadvantage than the wasp, with a quick movement, thrust his sting into the body of his foe, killing him easily and almost instantly. The experiment was repeated on the part of the wasp, and when there was no response from the inside he became satisfied, probably, that he held the fort. At all events, he proceeded to enter the nest and slaughter the young spiders, which were afterwards lugged off one at a time.
Mr. Henry Cecil writes as follows (Nature, vol. xviii., p. 311):—
I was sitting one summer's afternoon at an open window (my bedroom) looking into a garden, when I was surprised to observe a large and rare species of spider run across the window-sill in a crouching attitude. It struck me the spider was evidently alarmed, or it would not have so fearlessly approached me. It hastened to conceal itself under the projecting ledge of the window-sill inside the room, and had hardly done so when a very fine large hunting wasp buzzed in at the open window and flew about the room, evidently in search of something. Finding nothing, the wasp returned to the open window and settled on the window-sill, running backwards and forwards as a dog does when looking or searching for a lost scent. It soon alighted on the track of the poor spider, and in a moment it discovered its hiding-place, darted down on it, and no doubt inflicted a wound with its sting. The spider rushed off again, and this time took refuge under the bed, trying to conceal itself under the framework or planks which supported the mattress. The same scene occurred here; the wasp now appeared to follow the spider by sight, but ran backwards and forwards in large circles like a hound. The moment the trail of the spider was found the wasp followed all the turns it had made till it came on it again. The poor spider was chased from hiding-place to hiding-place, out of the bedroom, across a passage, and into the middle of another large room, where it finally succumbed to the repeated stings inflicted by the wasp. Rolling itself up into a ball the wasp then took possession of its prey, and after ascertaining it could make no resistance, tucked it up under its very long hind legs, just as a hawk or eagle carries off its quarry, when I interposed and secured both for my collection.
Mr. Belt, in his work already frequently quoted, gives the following account of a struggle which not unfrequently occurs between wasps and ants for the sweet secretion of 'frog-hoppers:'—
Similarly as, on the savannahs, I had observed a wasp attending the honey-glands of the bull's-horn acacia along with the ants; so at Santo Domingo another wasp, belonging to quite a different genus (Nectarina), attended some of the clusters of frog-hoppers, and for the possession of others a constant skirmishing was going on. The wasp stroked the young hoppers, and sipped up the honey when it was exuded, just like the ants. When an ant came up to a cluster of leaf-hoppers attended by a wasp, the latter would not attempt to grapple with its rival on the leaf, but would fly off and hover over the ant; then when its little foe was well exposed, it would dart at it and strike it to the ground. The action was so quick that I could not determine whether it struck with its fore-feet or its jaws; but I think it was with the feet. I often saw a wasp trying to clear a leaf from ants that were already in full possession of a cluster of leaf-hoppers. It would sometimes have to strike three or four times at an ant before it made it quit its hold and fall. At other times one ant after the other would be struck off with great celerity and ease, and I fancied that some wasps were much cleverer than others. In those cases where it succeeded in clearing the leaf, it was never left long in peace; for fresh relays of ants were continually arriving, and generally tired the wasp out. It would never wait for an ant to get near it, doubtless knowing well that if its little rival once fastened on its leg, it would be a difficult matter to get rid of it again. If a wasp first obtained possession, it was able to keep it; for the first ants that came up were only pioneers, and by knocking these off, it prevented them from returning and scenting the trail to communicate the intelligence to others.
Dr. Erasmus Darwin records an observation ('Zoonomia,' i., p. 183) which, from having since been so widely quoted, deserves to be called classical. He saw a wasp upon the ground endeavouring to remove a large fly which was too heavy for it to carry off. The wasp cut off the head and abdomen, and flew away with the thorax alone. The wind, however, catching the wings of this portion made it still too unwieldy for the wasp to guide. It therefore again alighted, and nipped off first one wing and then the other, when it was able to fly off with its booty without further difficulty.
This observation has since been amply confirmed. I shall quote some of the confirmatory cases.
Mr. R. S. Newall, F.R.S., in Nature, vol. xxi., p. 494, says:—
Many years ago I was examining an apple tree, when a wasp alighted on a leaf which formed a caterpillar's nest neatly rolled up. The wasp examined both ends, and finding them closed, it soon clipped a hole in the leaf at one end of the nest about one-eighth of an inch in diameter. It then went to the other end and made a noise which frightened the caterpillar, which came rushing out of the hole. It was immediately seized by the wasp, who finding it too large to carry off at once, cut it in two and went off with his game. I waited a little and saw the wasp come back for the other half, with which it also flew away.