THE COURTSHIP OF INSECTS 253 



of bees and two-winged flies, the visual organs often 

 occupying the greater part of the head-area ; and in all 

 such cases the male relies chiefly upon his enhanced powers 

 of vision in order to discover his mate. 



Certain nocturnal beetles emit a phosphorescent light, 

 our own glow-worm (Lampyris noctiluca) being a familiar 

 example. The female glow-worm is wingless, and differs 

 little from the larva in appearance ; but her light is in- 

 finitely more powerful than that of the winged, large- 

 eyed male. Thus there is reason for thinking that the 

 female's light attracts the male from a distance. These 

 conditions do not always obtain, however, for in some 

 species, such as the fire-flies (Lucio/a) of Southern Europe, 

 the males are more luminous than the females, and are 

 accustomed to form aerial bachelor parties on calm, warm 

 nights. Myriads of them may sometimes be seen moving 

 and sparkling in the darkness ; and Dr. Sharp suggests 

 that their lights may " serve as an amusement, or as an 

 incitement to rivalry " ; while we are free to believe that 

 the most brilliant suitors find special favour in the eyes of 

 the stay-at-home females. 



That the choice of the female is often the decisive 

 factor in insect courtship is admitted by many naturalists. 

 When dealing with the senses of insects we saw that cer- 

 tain male moths can track down individuals of the other 

 sex by scent alone ; yet the first male to arrive does not 

 always become the accepted mate. The courtship of the 

 antler moth {Charceas graminis) has been well described 

 by Professor Poulton. He tells us how the males assemble 

 from far and near round a freshly emerged female. The 

 suitors buzz in an excited crowd about the object of their 

 passion. Suddenly one is accepted, and all the others 

 immediately disperse. " In these cases the males do not 

 fight or struggle in any way, and as one watches the 



