LIVING LAMPS 225 



brightly luminous, giving off a light bluish green radiance. Tn 

 the pupae the tip of the body is also luminous, and the same 

 region in the adults emits a steady light about half as bright 

 as that of the young. 



The larvae of another fungus gnat which live gregariously 

 beneath a sticky web on the under side of certain toad-stools 

 are also luminous, their whole body shining. The pupae are 

 also luminous, but the adults are not. 



Some years ago the larva or grub of one of our click-beetles 

 {Mclanactes piceiis) was described as luminous and so figured; 

 but the figure represents a female fire-fly of the sort called 

 Phengodcs, a grub-like creature an inch and a half or so in length 

 with a series of bright lights on either side. This mistake has 

 been several times repeated. The same insect was at about 

 the same time recorded as a luminous milleped. 



Once in Trinidad a friend of mine, enjoying the refreshing 

 evening coolness in the Botanic Garden, saw some fiery teeth 

 suddenly appear before his face. Startled he jumped back, 

 and the teeth moved rapidly away. They were the teeth of a 

 large bat which had been eating fire-flies. Sometimes night 

 birds also render their mouths and beaks luminous by eating 

 fire-flies. 



Before leaving the subject of luminous insects it is perhaps 

 worthy of remark in this connection that an Indian bird has 

 the curious habit of catching fire-flies and sticking them in the 

 mud about its nest as if to serve as lamps. 



Among the creatures on the land the ability to give out light 

 is rather rare, perhaps because of the brilliant illumination by 

 the sun for twelve hours, more or less, each day. But in the 

 sea where animal life is most abundant, at some depth be- 

 neath the sun-lit surface and in the less illuminated regions 

 north and south, very many, if not most, sorts of animals 

 give out a light. 



An unusual exhibition of phosphorescence at the surface 

 was thus described by Lord George Campbell, one of the watch 

 officers on the "Challenger." 



