61 Eev. H. S. Gorham on the 



the female ; but I believe this to be the case only in a 

 special sense in those species which do not assemble, and 

 especially in those in which the females are incapable of 

 flight. In other cases I believe that hotli sexes are 

 attracted, and enabled by this means to assemble at night 

 for their union. These inferences are drawn from the con- 

 sideration of the relative development of the eyes, together 

 with what is known of the habits of the various species. 



The eyes of the Lampyridce are, I find, developed in 

 magnitude according to the amount of luminosity of the 

 species considered. And the other parts which I have 

 taken account of, together with these, are the antenna?, 

 of which there is a very great diversity, both between the 

 sexes, and in the genera ; — the elytra, which are also 

 subject to sexual and generic limitations, and finally the 

 size of the abdomen in the female. 



The last mentioned is no doubt, as in other apterous 

 females, the result of an increased production of ova. 

 These are, I believe, in the Lampyridce laid on roots, and 

 other substances near the ground, Avhcre the young larvo3 

 will at once be likely to meet with their molluscan diet. 

 The greater the tendency to produce ova in abundance, the 

 more sluggish the females would become, and hence females 

 once capable of flight would lose the use of their wings, 

 and the usefulness of the light to attract their more 

 volatile partners would be greater than ever. This I 

 believe to be the explanation of the fact that the highest 

 degree of light, or at any rate the greatest disproportion 

 in the amount shown by the sexes, is to be found in those 

 species which have apterous females, and together with 

 this the greatest development of eye in the male. We will 

 now consider the case of those species in which both sexes 

 are winged, and in which both are luminous, and in 

 probably nearly equal degree. Such are, I have reason to 

 think, by far the large proportion of the whole number of 

 existing species. In this case the power of emitting light 

 would be obviously useful in attracting both sexes to 

 assemble in swarms, and it does not militate against this 

 supposition that in many species the males should possess 

 this faculty in the higher degree. It might be anticipated 

 that if the female has to be guided to the rendezvous of 

 the species by this effect, the eyes in that sex would not be 

 inferior to those of the male ; and such is the fact. To 

 save repetition here I will only instance one well-known 

 case, viz., that of the European and Eastern genus 



