Thenceforward, till the young are hatched, the wolf-spider never quits her egg-bag, which she carries about on all her expeditions attached by threads to the spinnerets. Garden-spiders die soon after laying their eggs and never see their progeny, but here we have a case of maternal solicitude persisting for many days, and the Peckhams seized upon it as a good subject for investigating the subject of the memory of spiders. If the cocoon were removed from the spinnerets, after how long an interval would it be recognised by the mother? A _Pirata_ was selected for experiment. It offered great resistance to the removal of the cocoon, seizing it with its jaws and trying to escape with it. When it had been taken away the mother displayed great uneasiness, searching for it in all directions. It was returned to her after an hour and a half, when she received it eagerly and immediately attached it in the usual position. From three others of the same species the cocoons were removed and restored after thirteen, fourteen and a half, and sixteen hours respectively. All remembered them and took them back immediately. But twenty-four hours seemed to be the extreme limit of their memory; after that interval two of the mothers refused to have anything to do with their cocoons, while the third only resumed hers, slowly and without any enthusiasm, after it had been placed before her seven times in succession. Some other species seemed to possess a rather longer memory, but the experimenters found no Lycosid constant in her affection for so long a period as forty-eight hours. We have said that Lycosid spiders see comparatively well; yet, if they are placed within an inch or two of their cocoons they may be quite a long time finding them. This is very puzzling until it is considered that its habitual position is such that the spider never sees it. She never has seen it since its construction, and does not in the least recognise it by sight. Spiders of other groups, where the female remains near but detached from the cocoon, are not at the same disadvantage, and if the cocoon is removed to a short distance the mother will go straight to it and bring it back. The wolf-spider only knows the _feel_ of the cocoon; she may pass close by it without recognition, but as soon as she touches it the cocoon is immediately resumed—if the interval of separation has not been too great.