The actions of the spider make it quite evident that its power of sight is well developed. Mr and Mrs Peckham, whose remarkable observations on the mating habits of jumping spiders must presently be considered, established friendly relations with some of their captives which became so tame as to jump on their hands and take food from their fingers. They frequently induced them to jump from a finger of one hand to one of the other, gradually increasing the distance up to eight inches. They also twice observed a male chasing a female upon a table covered with jars, books and boxes. “The female would leap rapidly from one object to another, or would dart over the edge of a book or a box so as to be out of sight. In this position she would remain quiet for a few moments and then, creeping to the edge, would peer over to see if the male were still pursuing her. If he happened not to be hidden, she would seem to see him, even when ten or twelve inches away, and would quickly draw back.” Moreover that they have the ability to discriminate colours has been shown by their behaviour when imprisoned in cages consisting of a series of communicating chambers each with a glass top of a different hue. They show a marked preference for the red chamber under these circumstances while the least attractive colour seems to be blue. It has been known for a long time that the males of many kinds of birds—and especially of the more ornamental species—are accustomed to perform the most extraordinary antics in the presence of the female at the time of mating. The Peckhams made the unexpected discovery that precisely similar “love dances” took place in the case of the jumping spiders. Even the comparatively sober-coloured “zebra spider” performs a weird _pas seul_ in courting its mate, but its display is feeble compared with that of some of the more ornate of the Attidae. Certain isolated observations on captive jumping spiders led these observers to suspect that the mating habits were unusual and worthy of accurate investigation, and they laid their plans accordingly, taking their summer holiday a month earlier than usual, so as to miss nothing of the pairing season, and including in their party an artist whose drawings should furnish an indubitable record of the attitudes assumed by the male spiders in their evolutions.