356 NATURAL THEOLOGY. 



V. If the reader, looking to our distributions of 

 science, wish to contemplate the chemistry as 

 well as the mechanism of nature, the insect crea- 

 tion will afford him an example. I refer to the 

 light in the tail of a glow-worm. Two points seem 

 to be agreed upon by naturalists concen ing it: 

 first, that it is phosphoric ; secondly, that its use is 

 to attract the male insect. The only thing to be 

 inquired after is the singularity, if any such there 

 be, in the natural history of this animal, which 

 should render a provision of this kind more neces- 

 sary for it than for other insects. That singular- 

 ity seems to be the difference which subsists be- 

 tween the male and the female, which difference 

 is greater than what we find in any other species 

 of animal whatever. The glow-worm is a female 

 caterpillar f the male of which is a^i/, lively, com- 

 paratively small, dissimilar to the female in ap- 

 pearance, probably also as distinguished from her 

 in habits, pursuits, and manners, as he is unlike in 

 form and external constitution. Here then is the 

 adversity of the case. The caterpillar cannot meet 

 her companion in the air. The winged rover 

 disdains the ground. They might never there- 

 fore be brought together did not this radiant 

 torch direct the volatile mate to his sedentary 

 female.^^ 



*« The female glow-worm undergoes the same transformations 

 as all other insects, and its perfect state differs considerably from 

 its larva or caterpillar state, though in both stages it emits the 

 phosphoric light. Besides the ordinary sexual distinctions, the 



