Courtship of certain European Acridiide. 235 
Further evidence in support of this explanation is to 
be found in the fact that Pezotettiv makes the movement 
when he has succeeded in capturing the female and when 
pairmg 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 Stenobothrus 
hemorrhoidalis, and one on Stethophyma fuscwm, im 
which it is to be explained as an answer to another 
very persistent male). 
If, however, as I suppose, the movements of Pezotettia 
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 Pezotettiv may have a 
stimulating or perhaps merely a soothing effect on the 
female. 
The comparison between Pezotettiv 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 Gomphocerus a peculiar attitude was assumed, 
movement of some of the appendages of the head was 
made, ard 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. ‘hen, 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 stridulating 
