FAKMEES' INSTITUTES. 381 



during the night. The morning witnessed notliing but naked stems. So too 

 this year in the southern counties of our State, hundreds of acres of oats were 

 ruined by these hordes of destroyers. And though our State for the most part 

 wliolly escaped injury still these destructive raiders were very general in their 

 work of pillage, as Ave read account of their havoc, even from Massachusetts to 

 Missouri. 



We thus see that tlie word army-worm is no misnomer. The same word is 

 applied to another closely allied insect which plunders the cotton-grower of the 

 south. 



After the completion of their four weeks' glottony, the caterpillars having 



now completed their growth, descend into the earth for about 



two inches and become pupre (Fig. 3). As before intimated, 



this occurs during the month of August. In about three weeks 



Fig. 3. |;|j0 moths again come forth to mate, and in turn lay their one or 



two hundred eggs. 



WHY THEY COME IK SUCH NUMBERS. 



Prof. Kiley and Dr. Eitch think that they usually feed and dwell in marshes, 

 where they are confined, but that excessively dry years are very favorable to 

 their increase, so that many moths will be developed, and a corresponding num- 

 ber of eggs deposited. They also believe that a very wet year favors the growth 

 and development of the larvEe, so that when we have a very dry year succeeded 

 by one very wet, then we may expect raids from these ruthless destroyers. 



The experience of the past two years, as well as the previous cases carefully 

 elaborated in Dr. Fitch's 6th Keport, seem to sustain this view. Yet it may be, 

 and I incline to the oiDinion, tliat the peculiarity of the seasons has no such 

 direct agency in producing these unwelcome results. I have found that in com- 

 mon seasons I am quite as apt to take the larvaj of these moths in sweeping the 

 grass of high lands with my net as in sweeping the same in low or marshy places. 

 I believe that these insects would develop and lay eggs, whatever the season, 

 until they should sweep such plants as they feed upon out of existence, were it 

 not that nature, Malthus like, interferes to check the increase. 



That great philosopher and naturalist, Charles Darwin, has well shown that 

 there is a great struggle for life, in which the weak are overtaken and destroyed 

 by the strong. Now this constant warfare extends with superlative rigor to the 

 realm of insect life. The principle, though a general one, is best illustrated 

 among insects, since they so far outnumber all other animals. As Swift well 

 says : 



The little fleas that do us tease have lesser fleas to bite them ; 

 And these again have lesser fleas, and so ad infinitum. 



Now the army-worms, perhaps from ease of access, having no means for con- 

 cealment, are emphatically victims to this principle. In fact, though hundreds 

 of these larva3 were sent me the past season, still I did not rear a single moth. 

 Nearly all were so exhausted by living foes, eating their very substance, that 

 they even failed to pupate, and the few that did transform to pupa? were only a 

 little later in succumbing to the hungry parasites, which found their sleek, full- 

 fed bodies both home and food. But though I did not rear any of these moths, 

 I did rear millions of the tiny parasites, through whose active labors these far 

 larger insects, our dreaded pests, were brought to naught. I thus obtained no 



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