440 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 19i:j. 



Kirkland has computed that one pair of gypsy moths, if unchecked, 

 would produce enough progeny in eight years to destroy all the 

 foliage in the United States. 



A Canadian entomologist states that a single pair of Colorado 

 beetles, or potato bugs, as we call them, would, without check, in- 

 crease in one season to 60,000^000. At this rate of multiplication the 

 disappearance of the potato plant would not be long delayed. The 

 chinch bug, a fecund and destructive pest, has been found in a clump 

 of grass 8 inches in diameter to the number of 20,000. The progeny 

 of this colony alone, if unchecked, would soon become incomputable 

 hordes, devastating wide areas of the earth's surface. Those of you 

 who have been in South Africa probably have seen locusts in flight 

 which filled the air and hid the sun. What a potency for evil lies 

 hidden in the tiny but innumerable eggs of these ravening pests ! If 

 every egg was permitted to hatch and every young locust to come to 

 maturity, the consequences would be too dreadful to contemplate. 



The voracity of insects is almost as astounding as their power of 

 reproduction. The daily ration in leaves of a caterpillar is equal to 

 twice its own weight. If a horse were to feed at the same rate, he 

 would have to eat a ton of hay every 24 hours. Forbush says that a 

 certain flesh-feeding larva will consume in 24 hours 200 times its 

 original weight, a parallel to which, in the human race, would be an 

 infant consuming, in the first day of its existence, 1^500 pounds of 

 beef. Trouvelot, who made a special study of the subject, affirms that 

 the food taken by a single silkworm in 56 days equals in weight 

 86,000 times its original weight at hatching. What a destruction 

 this single species of insect could make if only a one-hundredth part 

 of the eggs laid came to maturity ! 



MISSION OF THE BIRDS IN ORGANIC NATURE. 



Who or what is it that prevents these ravening hordes from over- 

 running the earth and consuming the food supply of all ? It is not 

 man. Man, by the use of mechanically applied poisons, which are 

 expensive, unnatural, and dangerous, is able to repel to an extent the 

 attacks on his orchard and garden. Out in the fields and in the 

 forests he becomes, before any very great imiption of insects, a panic- 

 stricken fugitive. Neither is it disease, or the weather, or animals^ 

 or fungi, or parasitic and predaceous insects within their own ranks. 

 However large may be the share of these particular natural agencies 

 in keeping insects in check, experience has shown that it is lamentably 

 insufficient. Then what is it? The bird. Bird life, by reason of its 

 predominating insect diet, i§ the most indispensable balancing force 

 in nature. 



