Courtsliii) of certain European Acridiidse. 235 



Further evidence in support of this explanation is to 

 be found in the fact that Pezotettix makes the movement 

 when he has succeeded in capturing* the female and wheu 

 pairing has actually begun. In the other species ob- 

 served the normal arrangement was for the male to 

 stridulate apparently to charm or please the female before 

 leaping on her; stridulation after this occurring only in 

 certain special cases (one observation on 8tenobothrus 

 hmmorrlioidalis, and one on Stethopliyma fuscum, in 

 which it is to be explained as an answer to another 

 very persistent male). 



If, however, as I suppose, the movements of Pezotettix 

 are merely vestigial, we can quite understand their asso- 

 ciation in the nervous system with those stronger nervous 

 impulses which are concerned with the successful issue 

 of courtship, rather than with the impulses concerned 

 with courtship itself. According to this view the 

 functional stridulation is associated with anticipation 

 while the vestigial stridulation is only evoked by realiza- 

 tion. It should be added that it is quite possible that 

 these movements of the male Pezotettix may have a 

 stimulating or perhaps merely a soothing effect on the 

 female. 



The comparison between Pezotettix and the other 

 species supports in another way these conclusions as 

 to the essential significance of stridulation in courtship. 

 In the latter kinds, so far as they were sufficiently 

 observed, the female was treated with considerable cere- 

 mony ; in Gom2:)liocerus a peculiar attitude was assumed, 

 movement of some of the appendages of the head was 

 made, and the female was in some cases patted or stroked, 

 in addition to the most assiduous stridulation. The latter 

 was never omitted in any species in which we could detect 

 any sound. But the little male of Pezotettix, being appa- 

 rently without any power of charming the female, behaves 

 in a manner entirely different from any of the others 

 described below. He lies in wait, leaps on the female, 

 and captures her unawares. Then, when he is firmly 

 seated,, the male attempts to charm her by nibbling with 

 his mandibles, and perhaps by the effect of the alternate 

 movement of his third legs. 



The general impression left by the whole of the obser- 

 vations recorded below was favourable to the theory of 

 sexual selection, and to the view that the stridnlating 



