26 TRANSACTIOM;! OF THK IJJJN'OIS 



insect enemies and the smaller the number of substances operated upon, 

 the more exact becomes the generalization and the greater the number of 

 characters which are common, and as a natural consequence, the greater 

 becomes the probability of a feasible point of attack. 



Let me illustrate tiiis point in order that it may be clearly under- 

 stood, for it really forms the basis of what I have to say at this time. 



If we attempt to give a definition which will include all animals and 

 exclude every thing else, we shall find it exceedingly difficult to fix upon 

 any character which is universally permanent in this kingdom, and found 

 nowhere else, no matter how broad we make our definition. If we limit 

 ourselves to the articulates, we find the task much easier, and more than 

 one character which we can seize upon. If we take the Insect Class only, 

 we find the number of common characters considerably increased ; and 

 ■ so on as we descend to the order, family, etc. 



Now let us make a more direct application of this idea to the subject 

 before us. Thorough, clean culture is properly considered an important 

 agency in preventing and counteracting the attacks of injurious insects; 

 that is to say, other things being equal, as a rule, less injury by insects 

 will accrue under this method of culture, than under a careless, slovenly 

 system. 



It is true that this is a broad generalization, yet it constitutes the 

 very first step in systematizing operations against our insect foes. If you 

 undertake to define, in strict and concise terms, what clean and thorough 

 culture is, you will find that in order to make it applicable to the farm, 

 the garden, orchard and nursery, your definition will have to be much 

 broader and far more general than it would be if limited to horticulture 

 alone ; and if confined to the nursery, flower garden or peach orchard, it 

 becomes still more exact and definite. As a natural consequence, the 

 more characters there are in coumion, the more points of general defense 

 are presented. 



As stated m reference to the attempt to define an animal, I am 

 doubtful whether a simple, concise definition of clean and thorough cul- 

 ture, as applicable to all agricultural operations, can be framed ; and even 

 if limited to that embraced under the term Horticulture, it is still doubt- 

 ful, as few, if any characters, are common to all its operations. But 

 when we descend to the subdivision of the latter as the orchard, nursery, 

 etc., we find the task much easier, as characters, common to the various 

 operations under these separate heads, are greatly increased. 



This will suffice to illustrate the idea I am trying to present, and will 

 also furnish a reason for the division proposed. 



Now, it is evident to any one at all acquainted with the subject, that 

 in attempting to systematize horticultural operations, so far as they relate 

 to the war with injurious insects, we must select either the habits and 

 characters of insects, or horticultural 0])erations, as our basis, and carry 

 out the plan in accordance therewith. In other words, it must be based 

 upon insect characters, or upon methods of culture. 



Certain well-known facts, in reference to insect life and habits, afford 

 excellent characters for a systematic arrangement ; as for example, that 



