2I 4 
mals a balance. And not only is there a balance between 
plants as opposed to animals but there is a natural balance 
within the two kingdoms of life. For example, if a plant- 
feeding species of animal increases because of an abundant 
food supply, provision for an increase of the parasitic and 
predaceous enemies of the plant-feeding animal is brought 
about and its increase checked. As regards plants, only a very 
small per cent, becomes established. The seeds of some do 
not find a foothold in the soil, some are destroyed and many 
that eventually reach the soil do not germinate and others find 
their place already occupied by other plants and are crowded 
out. Other plants that germinate and have room to grow are 
killed by heat or cold, or lack of moisture. All this is what 
is termed the "balance of nature." This balance is destroyed 
in the more or less artificial conditions surrounding animals 
under domestication or plants under cultivation. This brings 
us to the economic phase of the subject, but before consider- 
ing that we will pass to the general discussion of insects. 
The term "insect" has a certain meaning to you. It is 
synonymous, no doubt, to "bug," or "pest," "blight," etc., and 
these like all common terms are more or less inaccurate. The 
conception is probably that one or all terms apply to anything 
that crawls or to any minute organism, or, even, in the case of 
an unrecognizable injury to plants, to an agent of an unknown 
nature, the injurious "bug" or "blight" being some mysterious 
unseen organism that will reveal itself only to those versed in 
the science of the subject. I want to assure you that insects 
are tangible. Science has revealed them and their work to us 
and the information on the one hand, and the insects on the 
other, await our study and observation. 
The insects comprise a low class of animals known as 
Hexopoda or Insecta. Hexopoda refers to the chief distinc- 
tive characteristic of insects, that is, their possession of six 
feet. Insecta refers to the segmentation of the body or "body- 
rings." The term "bug" is correctly applied only to a certain 
sub-order of insects of which the predaceous plant-bugs, the 
water-boatmen, and the bed-bug are examples. "Blight," as 
applied to insect injury, is incorrect, it being the common 
name of the fungus diseases of plants, these being low orders 
of plant life. Zoologically, insects are closely related to the 
mites, the spiders, the scorpions, the centipedes, etc., but aside 
from having six feet, are further distinguished from them by 
having the body divided into three well-defined parts and those 
parts supplied with certain characteristic appendages. If we 
had the time and were provided with some low r -power micro- 
scopes and some dissecting needles, we would collect some 
representative species, a grasshopper perhaps, and determine 
these parts. It would help us to understand its adaptability to 
its surroundings and mode of life. The slides which I have 
to show you are but a poor substitute. 
