28 USEFUL BIRDS. 
THE NUMBER OF INSECTS. 
The number of insect species is greater by 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 fled, as computed by him, than there are human 
beings on the entire face of the earth. A small cherry tree 
ten feet in height was found by Dr. Fitch to be infested with 
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 plant 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 speak, it would require eleven months’ 
labor at ten hours a day to complete the enumeration.! 
In the days of their abundance the Rocky Mountain locusts 
in flight filled the air and hid the sun. From the high peaks 
of the Sierra Nevada they were seen filling the yllays below 
and the air above as far as a powerful field glass could bring 
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. 293, 294. 
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