THE REASON WHY. 335 



" Because thy loving kindness is better than life, my lips shall praise thee." 

 PSALM LXIII. 



which their heads are marked, their wings, feet, &c., are being 

 formed. 



1317. Why, when the water is disturbed, do the larvae 

 descend more rapidly than the pupce ? 



Because the pupae are in a torpid condition, awaiting the 

 formation of their perfect organs. 



1318. Why are the flies able to escape from the water ? 

 Because, as their formation becomes perfected, and the fluids of 



the body of the pupa become absorbed in the production of the 

 light texture of the wings, &c., the body and its case become 

 lighter than the water, and rise and float upon the surface. The 

 pupa-case then forms a natural boat, from which the fly emerges, 

 BD<^ spreading its wings, enters upon the final state of its existence. 



Fig. 82. -THE PERFECT GNAT. ESCAPING PHOM THB PUPA-CASE. 



(Greatly magnified.) 



This interesting metamorphosis may be seen going on in the summer time, 

 in every pond, brook, and reservoir. A fine sunny morning calls up millions of 

 these little boats from beneath the surface, and the diver within that wouderfal 

 little boll breaks its sealed doors, and flies away to enjoy the bright sunshine. 



1319. Why are beetles denominated " coleoptera /"' 

 Because they have wings protected by horny sheaths ; the term 

 coleoptera signifies wings in a sheath. 



