OF THE GLOWWOBM (LAMPTEIS NOCTILTJCA). 43 



darkness may be also due to the withdrawal of nervous influence 

 and its employment in the action of the muscles ; and thus the sem- 

 blance of an act of volition may be given to what is owing to purely 

 vital and physical causes. This explanation appears probable from 

 the fact that the light is never completely extinguished in the anal 

 segment, in which the organs within are not easily removed from 

 contact with the tegument by the ventral muscles. It may be 

 necessary to bear these circumstances in mind, as we shall find 

 that they are of some consequence with reference to the right inter- 

 pretation of the nature of the light. 



It has been supposed by most naturalists (Kirby and Spence, 

 &c. # ) that the production and use of the light have immediate 

 reference to the function of reproduction,— a view in which I 

 entirely coincide, as it is not only in accordance with the facts now 

 stated, but with all the circumstances of the natural history of the 

 insect. It has been objected to this view by some, that the male 

 also is slightly luminous, but this fact in no way affects the con- 

 clusion with regard to the female. 



The male of Lampyris noctiluca, as every naturalist is aware, is 

 a winged insect with large organs of vision over the greater por- 

 tion of each side of the head. It is far less numerous than the 

 female, and is very rarely taken, except on calm evenings, while 

 hovering about, or when in company with the females shining most 

 vividly ; it is, however, allured by the presence of artificial light 

 (Westwood, Introduction, p. 248). The sole object of its life in 

 the winged state is to search out its partner j and as it takes no 

 food whatever when it has assumed the winged condition, its 

 period of existence is necessarily very brief, for it dies generally 

 after it has paired. The light of the female too, after the union of 

 the sexes, becomes greatly diminished, and soon after the depo- 

 sition of her ova — a proceeding which occupies a few days — she 

 also perishes ; so that in a week or two after the middle of July, 

 when almost every individual has deposited her ova or has died 

 unimpregnated, all traces of the light of the glowworm are extin- 

 guished. 



Like the females of most insects, the glowworm has her life pro- 

 longed for a considerable period beyond that of her congeners, if 

 she has not been impregnated. And the chances that some of the 

 females may not be impregnated are very great, as the males are 

 not only few in number, but their time of appearance, so far as my 



* Journal of a Naturalist, 1830, 3rd edit. p. 302 ; Westwood's Introduction, 

 1838, vol. i. p. 248. 



