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the end of her tail a little below the surface, and fixes her eggs to the rush or substance 

 she is settled on ; which, by means of the glutinous matter all eggs of this kind are sur- 

 rounded with, adheres sufficiently fast, and there remains till the heat of the sun has 

 brought the young animal into life ; which immediately on quitting its confinement sinks to 

 the bottom, or repairs to the place where nature directs it to seek out its food. 



" In this manner all the slender-bodied tribe behave, differing only in some particular 

 circumstances ; as, for instance, the largest Libellas, as that at Fig. 5. PI. iTJ. are not near 

 so long in copulating or wooing as the small ones ; for by the former this act is performed 

 in a very short space, and while they are flying about in the air. Others, of a smaller 

 size, are less quick in this performance ; and as we descend to the smallest species, we 

 shall find they take by much the longest time ; observing, by the way, that all these slender- 

 bodied ones lay their eggs in the same manner, that is, by fixing them to some substance 

 to which they adhere, till they are ripened into life. My experience well informing me 

 they never scatter them in any loose careless manner as some insects do, but are placed in 

 such proper and apt situations as to receive the influence of the sun to bring them to 

 maturity. 



" If we attentively consider these creatures, either in their caterpillar or complete 

 states, we cannot help concluding them to be a rank of beings of greater benefit and advan- 

 tage to mankind than they appear to be at first view ; for, not to mention their being 

 annual 'ministers of nature,' they are appointed by the great Governor of the universe as 

 grand instruments for assisting to preserve that equilibrium so apparently reigning through 

 the insect world, and which all who have made any progress in the study of natural history 

 unanimously confess. Hence the voracious disposition of the Libellas is wisely made to 

 answer a most necessary and beneficial purpose ; and the great numbers of small insects 

 which are daily sacrificed to their insatiable appetites, both in their caterpillar as well as 

 complete states, is as strong an instance as any I know of the necessity and propriety of 

 the existence of these animals. The general principle reigning through the whole animal 

 kingdom, of the stronger prejing upon the weak and defenceless, can hardly be explained 

 to the purpose of being useful to mankind, and agreeable to the laws of nature, in any one 

 instance more than is evidently to be observed in the subjects I have been describing. 

 The least reflection wiU confirm this ; for if the food of the Libellas when in their com- 

 plete forms had consisted of the leaves of plants, like the locust genus, and not of those 

 small insects they now prey on ; or had it, like the beetle tribe, consisted of the superfluous 

 parts of nature, as the putrid carcases of dead animals, rotten wood, &c. how great a chasm 

 would there have been in the universal chain ? how evident and conspicuous would it have 

 appeared ? and how could the vast number of small insects, increasing every day during 

 the summer, be restrained and lessened ? what genus of the transparent- winged class could 

 possibly have performed this business singly ? or could all the genera of flies, and even 

 birds that we know of, have accomplished this end ? could all the Dipterae, or any other 



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