In a private letter, from which he kindly allows me to quote, Dr. Peckham says: “We have recently made some experiments on this wasp (_Sphex ichneumonea_). First we allow her to carry in her prey undisturbed, to see how far she was faithful to the traditions of her ancestors, and to observe her normal methods. On the next day, when she had placed her grasshopper just at the opening of the nest, and while she was below, we drew it back to a little distance. She came out, and we both repeated our operations four times--she running down into the nest, always after getting the grasshopper into position, and we as regularly drawing it away. The fifth time she changed her plan, seized it by the head and backed into the nest with it. The next day, at the fourth trial, she straddled it and walked head first into the nest with it; and on the fourth day, at the eighth trial, she backed in with it as on the second day.” These interesting observations show that the wasp has sufficient intelligence to modify her procedure in accordance with an unwonted situation. The “consecutive necessity,” as it has been termed, has a potent influence, but is not absolute. Fabre notes a case of similar consecutive necessity in the case of the mason bee, _Chalicodoma_. If while a bee is provisioning its nest with honey and pollen the structure be destroyed, she sometimes breaks open a completed cell, and, having done so, goes on bringing more provision, though the cell already contains a sufficient store of food; and only when she has completed the superfluous storing does she deposit her egg and seal up the cell. So, too, when the cell is removed in an early stage of construction, and another completed cell already partially stored is substituted, the bee, instead of simply adopting the new cell, goes on building until the cell is as much as one-third beyond the usual height; then, and not till then, does she proceed in due course to the next stage of the instinctive procedure, the provisioning of the cell.