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THE AMERICAN ENTOMOLOGIST. 



tent upon every such willow-busli throughout 

 the length and breadth of North America, and 

 thereby anniliilating the species from off the 

 face of tlie earth? Female Sawflics usnally lay 

 at least two or three hundred eggs. What pre- 

 vents this Sawfly from increasing a hundred 

 fold every year, till, at this rapid geometrical 

 rate of progression, it becomes as numerous as 

 the house-flies in a grocer's store in the latter 

 part of the summer?" Our readers can, we 

 think, now answer all these questions without 

 difficulty. Truly says Charles Darwin, that 

 with every organism on the face of this earth 

 there is a perpetual Struggle for Existence. 

 The Willow-apple Sawfly is striving every year 

 to fulfil the great law of Nature—" Increase and 

 multiply and replenish the earth." In its 

 efforts in this direction it is more or less checked 

 and controlled every year by the three distinct 

 Guest-insects that, in order to occupy for their 

 own greedy purposes the snug little house and 

 home of the poor gall-making larva, and feed 

 on the delicate pulp provided with such careful 

 forethought for its use, put it ruthlessly to 

 death. The Guest-insects, as well as the Gall- 

 maker, are in their turn checked and controlled 

 by different Parasites. And all of them, 

 whether Gall-makers, Guest-insects, or Para- 

 sites, are preyed upon to a very considerable 

 extent— especially alter they have left the gall 

 and are flying around for purposes of love, or 

 food, or enjoyment, or the search of suitable 

 homes for their future progeny — by Cannibal 

 Insects, by various Birds, and by diflerent kinds 

 of insect-devouring reptiles, such as Snakes, 

 Frogs and Toads, or insect-devouring Mammals 

 such as Skunks, Shrew-mice and Bats. Can 

 any one wonder that, in so complicated a sys- 

 tem as this, the balance occasionally oscillates 

 a little one way or the other? To us, instead of 

 our being astonished at the fact that certain in^ 

 sects— such for example as our Northern Army 

 Worm— occur in certain years in exorbitant 

 profusion, it seems like a perpetual miracle that 

 so very few disturbances occur in the great 

 System of Nature ; and that species do not con- 

 tinually eat up and annihilate species, year after 

 year and century after century, till at length 

 there remains nothing but one vast Bloated 

 Bug, who will finally .die of starvation, because 

 all his compatriots have been already swept 

 from ofi" the face of this green earth, and not a 

 single bug now remains for him to prey on. 



It is very true that, in the case of Insects, we 

 do not know for certain that many distinct spe- 

 cies may not have been annihilated by natural 

 causes within the last few centuries ; for ento- 



mology, as a science, dates only from the days 

 of Linnffius or about a hundred years ago; and, 

 even at the present day, what we know about 

 the Natural History of Insects is but as a drop 

 in the ocean when compared with the vast illim- 

 itable unknown. But let us recur to those 

 larger animals, such as Birds, which are only 

 about one-fiftieth a? numerous in species as In- 

 sects, and consequently do not cover so extensive 

 a field ; and which, from their far larger size, have 

 been studied mucli more carefully than Insects, 

 and for a very much longer time. So far as we 

 are aware, there arc but two Birds — the Dodo 

 of the Mauritius and the Great Auk of the 

 Arctic Regions — which within the memory of 

 man have become extinct; and even these, as 

 there is every reason to believe, have perished 

 from off the fiice of this earth, not through the 

 attacks of any of the inferior animals, but 

 through the unintermitting persecutions of 

 Man. Reasoning, therefore, from analogy we 

 may infer that scarcely any insects have become 

 extinct within historic times ; for, from their 

 generally very minute size and their occurring 

 usually in such immense swarms, it is impossi- 

 ble for Man, with all his boasted pre-eminence 

 as the King of the Creation, to AVage a war of ex- 

 termination against them. So true is it that — 

 within the very limited epoch reached by human 

 records — although the individual is annually dy- 

 ing, the species maintains a permanent foothold. 

 The Great Author of Nature took as much 

 pains — and we desire to be understood here as 

 speaking in no irreverent spirit— in making the 

 apparently insignificant little Sawfly whose his- 

 tory we have been tracing, as in building up a 

 Whale or an Elephant. Its habits are to the 

 full as interesting and instructive as those 

 of any of the larger animals. Its structure, 

 when examined with the aid of proper glasses, 

 is seen to be as complicated and wonderful even 

 as that of Man himself. And yet the majority of 

 mankind go through life with their eyes shut to 

 this little microscopic world of wonders, and look 

 down with contempt, forsooth, upon those who 

 have devoted half their years to the study of such 

 trifling little objects! Why? Simply because 

 a Bug is smaller than a Bear ! As if it could 

 ever be beneath the dignity of the Creature to 

 study those organisms, which it did not dero- 

 gate from the power and majesty of the Creator 

 to call into life by the fiat of his almighty will ! 

 As if, because a whale is a thousand times as 

 bulky as a man, therefore its history is a thou- 

 sand times more worthy to be carefully investi- 

 gated than that of man himself ! As if, because 

 Daniel Lambert weighed one thousand pounds, 



