14 



Probably the best known direct observation in support of the 

 * luminous insect ' theory of the Will-o'-the-Wisp is that given by 

 Kirby and Spence, related by the Rev. Dr. Sutton of Norwich. A 

 farmer, of Ickleton, Cambridgeshire, " brought to him a mole 

 cricket {Gryllotalpa vulgaris, Latr.j, and told him that one of his 

 people, seeing a Jack-o'-Lantern, pursued it and knocked it down, 

 when it proved to be this insect, and the identical specimen shown 

 to him." 



As to the accuracy of this observation I shall have something to 

 say later. 



Another account of the actual capture of a Will-o'-the-Wisp is 

 recorded by Mr. J, Main [Ann. Nat. Hist., vol. cit., p. 548). He 

 relates how " travelling by coach through Dedham Vale someone in 

 the company mentioned that it was famous for Will-o'-the-Wisps 

 seen dancing about on nights. His companion, a farmer, 

 immediately exclaimed that all the world was mistaken with respect 

 to this delusive light, for, said he, ' it is nothing but a fly,' and 

 related how he once saw one hovering over the backs of some cattle 

 he was driving and struck it down with his stick. He picked it up, 

 but its light was extinguished, and it appeared exactly like a 

 Moggy-long-legs. (? Tipula.)" 



Of course, it has been objected that the story of the mole cricket 

 requires confirmation, that a mole cricket is not ordinarily luminous^ 

 and that if it were to become so, frequently enough to give rise to 

 the popular conception of the Will-o'-the-Wisp, other observers who 

 have kept the insect in captivity could hardly fail to have found it 

 on occasions to be luminous. The advocates of this solution of the 

 mystery point out that certain other insects, as we shall see later, 

 not normally luminous, have been definitely ascertained to become so 

 sometimes, when in a diseased condition, owing to the presence of 

 luminous bacteria in their bodies; and that being so there is no 

 j)n)na facie reason why mole crickets should not become similarly 

 attacked and luminous. Such a contention does not perhaps 

 transcend the bounds of possibility, but what is the probability of 

 such being the true explanation of the phenomenon we are 

 considering ? 



You will note also that nothing further is said about the mole 

 cricket being luminous. Now surely had you or I had a mole 

 cricket brought to us with such a story we should have carefully 

 observed it after dark to see if it were really so. The presumption 

 is, therefore, that it was not ! 



