SCORPIONS, SPIDERS AND CRABS 243 



together at one time, must not be lost sight of ; nor must 

 we forget that they worked under the firm conviction 

 that the Sexual Selection theory of choice by the females 

 was an indisputable fact. Wherever colour was present 

 they looked for, and saw, evidence that the female 

 appreciated such hues, though from their observations it 

 would seem that dull-coloured species behaved as though 

 they were suffused with resplendent hues. In the course 

 of their studies the courtship of several species was in- 

 vestigated, but a summary of their results is all that can 

 be given here. Saitis pulex formed the subject of one of 

 their experiments. A male was placed in a box con- 

 taining a mature female. " He saw her as she stood 

 perfectly still, twelve inches away ; the glance seemed to 

 excite him and he moved towards her ; when some four 

 inches from her he stood still, and then began the most 

 remarkable performance that an amorous male could 

 offer to an admiring female. She eyed him eagerly, 

 changing her position from time to time so that he might 

 be always in view. He, raising his whole body on one 

 side by straightening out the legs, and lowering it on the 

 other by folding the first two pairs of legs up and under, 

 leans so far over as to be in danger of losing his balance, 

 which he only maintains by sidling rapidly towards 

 the lowered side. The palpus, too, on this side was 

 turned back to correspond to the direction of the legs 

 nearest to it. He moved in a semicircle for about two 

 inches, and then instantly reversed the position of the 

 legs and circled in the opposite direction, gradually 

 approaching nearer and nearer to the female. Now she 

 dashes towards him, while he, raising his first pair of 

 legs, extends them upwards and forwards as if to hold 

 her off, but withal slowly retreats. Again and again he 



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