168 COMMON BEETLES. 



female is the more powerful. The two sexes are 

 very different in appearance, as may be seen by 

 reference to the plate, fig. 1 being the male, and 1 a 

 the female. The object of the light is by no means 

 certain, nor the mode in which it is produced. 



On the same plate, fig. 11, is seen the Oil-beetle, 

 an eccentric kind of insect, which, when frightened, 

 pours a drop of oil out of every joint, just as if it 

 were a walking oil-barrel with self-acting taps. 



One of the commonest beetles, the Ground-beetle, 

 is seen on the same plate, fig. 10. There are very 

 many ground-beetles, but this is one of the hand- 

 somest and most conspicuous. The embossment of 

 its upper surface is worth a close examination, and 

 its colouring is peculiarly rich and deep. 



Hot sunny days always seem to bring out a host 

 of insects, among which the Sun-beetles are notable 

 examples. One of these insects is shown on plate 

 D, fig. 6. They are beautifully brilliant as they run 

 among the gravel-stones or over paths, their smooth 

 surface glittering in the sun resplendently. 



As an aquatic balance to the terrene Sun-beetles, 

 the Whirligigs (plate F, fig. 4) make their appearance 

 on the surface of the water on any light sunny day. 

 What rule they observe in their mazy dance is more 

 difficult to comprehend than the "Lancers," or a 

 cotillon : but that there must be a rule is clear from 

 the wonderful way in which they avoid striking 

 against each other in their passage. 



