i62 POPULAR SCIENCE MONTHLY. 



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 cephalo- 

 thorax and legs and a smoky abdomen, the colors being not widely 

 different. But, after the last molt, the male is simply unrecog- 

 nizable. He emerges a handsome, very alert creature, that runs 

 about openly by day a habit I think unknown in the Ctenizidae. 

 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 eresidse, 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 appear- 

 ance 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. 



