Page:Popular Science Monthly Volume 62.djvu/168

162 up to the last molt, identical with the female in size, color and shape, becomes quite another being in every respect afterwards. The female and immature males and young have a light brown cephalothorax and legs and a smoky abdomen, the colors being not widely different. But, after the last molt, the male is simply unrecognizable. He emerges a handsome, very alert creature, that runs about openly by day—a habit I think unknown in the Ctenizidæ. His magical change is no less radical in character than in appearance. His cephalothorax and legs are black, except that the front pair of legs, which are considerably elongated, have the fore parts white; his abdomen is black underneath, with a thin band of black round the sides, while the upper part is bright yellow. He moves alertly, often in a series of short rushes, and, if interfered with, does not feign death, like the rest of the eresidæ, but fights promptly and viciously, raising his body in front, lifting his forelegs on high and shaking the white parts angrily at you. To anything near his size he must be a most terrifying object.

Now, why this wonderful change in appearance and habits? Why he has adopted the habit of running about by day, I do not know. But, having done so, I cannot help thinking that his changed appearance and habits may have been evolved as a protection to him. At the time of the year when he appears, a very vicious ant (Camponotus fulvipilosus) is common over the veld during the day. The adult male eresid closely resembles this ant in color and style of movement. The ant, like the eresid, has a black head, thorax and legs and a yellow abdomen, and it moves in rushes. The resemblance is so close that, when I first saw the eresid, I took it, for a moment, to be the ant, and when I sent it to Dr. Purcell I described it as 'ant-like.'

No such spider as this eresid was previously known in South Africa. Dr. Purcell says it forms a new genus. I have sent several of its nests in situ to Cape Town. This could be done sucessfully only by melting hard paraffin and then pouring it into the sand around the nest, letting it soak up to the lid. Then, when the paraffin had hardened in the sand and bound it together, the nest could be removed in perfect order. The paraffin may be removed from the lid by treating it with warm oil of turpentine. Dr. Purcell will some day give detailed descriptions of all the interesting spiders and other things I have chatted about, with sketches of them and the nests in situ, and then we shall be able to call them by the names they will receive from him. Meanwhile I have thought a popular account of some Hanover arachnids might prove interesting.