INSECTS. 



107 



COLEOPTERA. 



Fig. 84. 

 PtINUS (MAGNIFIED). 



Fig. 85. 

 Male Glow-worm. 



Fig. 8G. 

 Female Glow-wohm. 



Among the various tribes of beetles constituting the present 

 order, very great difference exists even in our native species, 

 in size and colouring. The great water-beetle (Dytiscu^ 

 marginalis) is sufficiently powerful to play the tyrant of the 

 pool in which he lives, and even to attack and overcome small 

 fishes. Others, again, are so minute, as to live in the per- 

 forations they make in the timber of our dwelling-houses, and 

 thus to escape detection by ordinary observers.* Among 

 the latter may be mentioned those little beetles {Fig. 84), to 

 which vulgar superstition has given the name of " Death- 

 watch." 



" The solemn Death-watch click'd the hour she died." — Gay. 



This sound, which is only the call of the insect to its com- 

 panion, has caused many a heart to throb with idle fears, 

 which a slight knowledge of natural history would for ever 

 have dispelled. It so exactly resembles the ticking of a 

 watch, that Mr. R. Ball, by placing his watch to the wainscot 

 which the little beetle frequented, has caused the insect to 

 respond to its ticking. 



The structure of the mouth and of the wings has already 



* Mr. Spence has given an interesting account of the destruction of 

 large beams of tinibur in the dwelling-houses at Brussels, by one of those 

 in-sects. " The mischief," he says, " is wholly caused by Anobium 

 tessellatum which thus annually puts the good citizens of Brussels to an 

 expense of several thousand pounds, much of which might have possibly 

 been always saved, had the real cause of the evil been known.'' — Trans- 

 actions of the Entomological Society, vol. ii. page 11. 



