LUMINOUS INSECTS. 549 



may probably have a different object. Thus in the lantern-flies (Fulgora), 

 whose light precedes them, it may act the part that their name imports, 

 enabling them to discover their prey, and to steer themselves safely in the 

 night. In the fire-flies (Elater), if we consider the infinite numbers, that 

 m certain climates and situations present themselves every where in the 

 night, it may distract the attention of their enemies or alarm them. And 

 in the glow-worm — since their light is usually most brilliant in the female ; 

 in some species, if not all, present only in the season when the sexes are 

 destined to meet, and strikingly more vivid at the very moment when the 

 meeting takes place^ — besides the above uses, it is most probably intended 

 to conduct the sexes to each other. This seems evidently the design in 

 view in those species in which, as in the common glow-worm {L. nocti- 

 lucd), the females are apterous. The torch which the wingless female, 

 doomed to crawl upon the grass, lights up at the approach of night, is a 

 beacon which unerringly guides the vagrant male to her "love-illumined 

 form," however obscure the place of her abode. It has been objected, 

 however, to this explanation, that — since both larva and pupa, as De Geer 

 observed^, and the males shine as well as the females — the meeting of the 

 sexes can scarcely be the object of their luminous provision. But this 

 difficulty appears to me easily surmounted. As the light proceeds from a 

 peculiarly organized substance, which probably must in part be elaborated 

 in the larva and pupa states, there seems nothing inconsistent in the fact 

 of sojne light being then emitted with the supposition of its being destined 

 solely for use in the perfect state : and the circumstance of the male 

 having the same luminous property, no more proves that the superior 

 brilliancy of the female is not intended for conducting him to her, than 

 the existence of nipples and sometimes of milk in man proves that the 

 breast of woman is not meant for the support of her offspring. We often 

 see without being able to account for the fact, except on Sir E. Home's 

 idea, that the sex of the ovum is undetermined^, traces of an organization 

 in one sex indisputably intended for the sole use of the other. 



I am, &tc. 



' Mailer in Illig, Mag. iv. 178. « iv. 49. ^ p/jj/. j^^ans. 1799, 157. 



