28 USEFUL BIRDS. 



THE NUMBER OF INSECTS. 



The imnil)cr of insect species is greater hy far than that 

 of the species of all other living creatures combined. More 

 than three hundred thousand have been described. There 

 are many thousands of undescribed species in museums. 

 Dr. Lintner, the late distinguished State entomologist of 

 New York, considered it not improbable that there were a 

 million species of insects. The number of individual insects 

 is beyond human comprehension or computation. 



Dr. Lintner says that he saw at a glance, in a small extent 

 of roadway near Albany, more individuals of a single species 

 of snow flea, as computed by him, than there are human 

 beino-s on the entire face of the earth. A small cherry tree 

 ten feet in height was found by Dr. Fitch to be infested witli 

 an aphid or plant louse. He estimated (first counting the 

 number of these insects on a leaf, the number of leaves on a 

 branch and the number of branches on the tree) that there 

 were twelve million })lant lice on the tree ; and this was only 

 one tree of a row similarly infested. To give the reader an 

 approximate idea of the number of insects on the tree, it 

 was stated that, were a man to count them singly and as 

 rapidly as he could s})eak, it would require eleven months' 

 labor at ten hours a day to complete the enumeration.^ 



In the days of their abundance the Rocky ^lountain locusts 

 in flight filled the air and hid the sun. From the high peaks 

 of the Sierra Nevada they were seen filling the valleys below 

 and the air above as far as a powerful field glass could ])ring 

 the insects within focus. The chinch bug in countless mil- 

 lions infests the grain fields over towns, counties, and States. 

 The army worm moves at times in solid masses, destroying 

 the crops in its path. 



THE REPRODUCTIVE CAPACITY OF INSECTS. 



Insects are enormously productive, and, were the progeny 

 of one pair allowed to reproduce without check, they would 

 cover, in time, the entire habitable earth. 



* Our Insect Enemies, by J. A. Lintner. Sixteenth Annual Report, New 

 Jersey State Board of Agriculture, 1888-89, pp. 2i«, 294. 



