38o THE PLACE OE MIMICRY 



display was made by Geori:,^e \V. and Elizabeth G. Peck- 

 ham upon spiders of the famil\' ^Ittidixc} These obser- 

 vations aft'orded the authors ' conclusive evidence that the 

 females pay close attention to the love dances of the 

 males, and also that they have not only the power, but 

 the will, to exercise a choice among the suitors for their 

 favor*. Observations on the courtship of grasshoppers 

 have also yielded some support to the Darwinian hypo- 

 thesis of Sexual Selection. - 



Epigamic characters are often concealed except during 

 courtship : they are found almost exclusively in species 

 which are diurnal or semi-diurnal in their habits, and are 

 excluded from those parts of the body which move too 

 rapidl)- to be seen. They are very commonly closely 

 associated with the nervous system ; and in certain 

 fish, and probably in other animals, an analogous 

 heiirhtenincr of effect accompanies nervous excitement 

 other than sexual, such as that due to fighting or 

 feeding. 



Although there is Epigamic display in species with 

 sexes alike, it is usually most marked in those with 

 Secondary Sexual Characters specially developed in the 

 male. These characters are an exception to the rule in 

 heredity, in that tlieir appearance is normally restricted 

 to a single sex, although in many of the higher animals 

 they have been proved to be latent in the other sex, and 

 may appear after the essential organs of sex have been 

 removed or rendered functionless. The 'higher animals' 

 must in this respect be held to include the insects, inas- 

 much as a development of these latent characters occurs 

 in bees when the essential reproductive glands have been 

 destroyed by the parasitic Sty lops. Wallace suggests that 

 Epigamic Characters are in part to be explained as 

 Recognition Marks, in part as an indication of surplus 

 vital activity in the male.^ 



* Occasional Papers of the Natural History Society of Wisconsin, vol. i, 

 1889, Milwaukee: Observations on Sexual Selection in Spiders of the 

 Family Attidae. 



^ Trans. Ent. Soc, Land., 1896, p. 233. 



' See especially Darwinism, London, 1889, pp. 268-300. 



