418 ORDERS OF PTILOTA. 



folded upon the breast. In the others the metamorphosis 

 is effected by the larva shedding its skin, and the insect then 

 appearing in the form of an inactive incomplete pupa, like 

 that of the former, but not inclosed in a cocoon. In some 

 of the latter, as in the aquatic species, the pupa retains its 

 activity, jerking about with much agility in the water, whilst 

 many are quite inactive. 



In their perfect state, the insects of this order are scarcely 

 less numerous, in point of species, than any other order of 

 insects ; but, if we look at them with respect to the number 

 of individuals, we find them infinitely to exceed any other. 

 The clouds of midges {Chironomus), for instance, rising at 

 eventide over the marshes, like the incense of the Temple, 

 equally pay homage to the Divinity, in showing forth His 

 mighty power ; whilst myriads of flies of every kind are to 

 be found in every quarter of the globe, traversing plants and 

 every animate object, and more particularly aU that has ceased 

 to live. 



This immense profusion with which they are dispersed 

 over the globe causes them to fulfil two very important 

 functions in the economy of nature. First, they serve for food 

 to a vast number of the higher animals. Charged with a 

 Divine mission by Him " who giveth food to the young bird," 

 the swallow and the sparrow destroy them by myriads, and 

 the fly-catcher and the humming-bird alike find in them a 

 constant shedding of manna ; whilst, in the second place, 

 they cease not in effecting the disappearance of aU substances 

 in a state of decomposition, both animal and vegetable. They 

 are universal scavengers ; and so great is their activity, and 

 the rapid succession of their generations, that Linnaeus might 

 well say that three flies can consume a horse as fast as a lion. 

 Amongst such a vast number of objects, it is not surprising 

 that some shoidd be found obnoxious to ourselves or our 

 properties. Many species, accordingly, cease not to make 



