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JV. Study of Injurious Insects and Methods of Controlling 

 Them. 



Insect life, like all other forms of life, travels in a cycle. 

 As in a cycle there is no definite beginning or end. On and 

 on it rolls from father to son and from son to father. Full 

 grown females produce eggs, from which hatch young, which 

 after a certain period of growth, become mature and lay eggs 

 in turn. The length of time consumed between any one stage 

 in the life cycle and the same stage beginning the next cycle, 

 as between egg and egg, varies with the species (kind) ot 

 insect, with the temperature and other climatic conditions. 

 In the temperate zones, the active life of most living objects, 

 plants and animals, is interrupted by the winter months. 

 During cold weather most forms of life remain at a stand- 

 still. The number of life cycles that any one species of in- 

 sects would complete in a course of a year is thus reduced. 

 Such is not the case in a salubrious, sub-tropical climate like 

 ours. All forms of life continue in activity the year around. 

 No stage of the cycle is omitted ; neither is any stage of it 

 extended because of cold, though normal variation due to 

 tluctuation in temperature and moisture is bound to take 

 place. Thus a species of insects that on the mainland pro- 

 duces from one to three broods, as cycles are sometimes called, 

 if established here, breeds practically continuously and pro- 

 duces perhaps twice as many broods. The seeming calamity 

 is atoned for by the equally rapid growth of vegetation. 

 Where one crop a year is raised on the continent, two and 

 three are grown here. Naturally, the more crops we raise 

 upon a given area in course of the year the more attention 

 we must devote to that area ; in exact proportion to the num- 

 ber of crops and care given to a similar area in a colder climate 

 on the mainland. 



In a new environment the behavior of insects will change. 

 The climate, amount of food, and number of natural enemies 

 contribute toward this behavior. As said before, practically 

 all of our injurious insects are of foreign origin, and, except 

 those that are also injurious in the United States, little is 

 known about their habits. We fight injurious insects with 



