17 



find it, and groping among the herbage found what he at once 

 assumed to be the creature he was seeking, but that the Mole Cricket 

 thus found had no connection whatever with the Will-o'-the-Wisp. 



Now destructive criticism is all very well, but, you may ask, 

 have I anything more likely to suggest in place of the Mole Cricket ? 

 I think we are justified in assuming a luminous insect, or apparently 

 luminous insect, to be the cause of the apparitions we have so far 

 considered. Also I fail to find any satisfactory explanation of a truly 

 luminous insect capable of producing this kind of appearance; but 

 " apparently luminous insect ; " I think that gives us a clue. Many 

 of you lepidopterisis when out dusking or later on a June evening 

 have no doubt seen the appearance of a shining luminous object 

 hovering in one spot for a time, then moving off to repeat the 

 motions a few yards away, then oft" again, and then disappearing 

 altogether, only to appear again a few moments later. You 

 know it at once to be a male Ghost Swift Moth displaying 

 his attractions in the hope of finding a mate. But would the 

 average countryman know it for such ? Would it not appear to 

 him as indeed a pale light hovering over the herbage ? You have 

 heard of the Will-o'-the-Wisp perhaps, and know it to be caused by 

 the spontaneous ignition of marsh gas given oft" by the decomposition 

 of organic substances, so that there is no connection in i/aiir minds 

 between it and the Ghost Swift; but he sees this pale hovering light 

 and has heard his father or his grandfather describe the Will-o'-the- 

 Wisp ; and the identity of the two is obvious. Then when he 

 knocks it down, it falls back downwards, or with only the underside 

 of the wings exposed, and in the darkness is practically invisible. 

 No wonder then that when he finds an extraordinary looking animal 

 like a Mole Cricket he at once jumps to the conclusion that that 

 was what he knocked down. 



It is well to bear in mind, too, the traditional appearance of the 

 Will-o'-the-Wisp ; it is described as a ' phosphorescent' light, i.e., it 

 does not look like an actual flame, but is a pale shining luminosity 

 suggesting phosphorescence, which is exactly the appearance of the 

 male Ghost Swift. 



That the Ghost Swift is the substantial basis of this class of 

 phenomena appears to some extent to be confirmed by the following 

 paragraph that; appeared in the Westminster Renew in October, 

 1832 (reprinted in Kut. Ma<i., 1833, p. 216). 



'' Ji/nis Fatuiis. This appearance has been strongly surmised to 

 be a luminous insect. It is many years since the similarity of its 



