50 



TKTRODVCTORY. 



thoroughly understand the natural history and habits of those 

 parasites that prey upon his industry, and can therefore make 

 a successful warfare f<»r tlieir externiination, having a complete 

 knowledge of how and when to j^trike the blow for victory. 



CHAPTEK XV. 



Economic Entomology. 

 Ilortii-uhurists and all other ])ers(>ns engaged in cultivating 

 the soil sliould make the study of insects (especially those 

 known to be injurious to fruit and fiiiit trees, grtiin, vegeta- 

 ta))les. etc.), a part of their every day work. It is as necessary 

 for them to understand the natural history and habits of such 

 pests of the orchards, etc., as it is to understand how to plant, 

 prune, etc. 



Some fruit-growers think that for such jtractical investiga- 

 tion of insect life, a scientifi<' knowledge of the anatomy and 

 physiology of these creatures is indispensable. Such, how- 

 ever, is not the case. It requires some apparatus (which can 

 be procured at a nominal expense), a little patience, and an 

 interest in the subject investigated, to learn practically what 

 they have depended on others to furnish. 



The following apparatus is necersarj^ : (I am under oljliga- 

 tions to Mr. C. Muller, optician. No. 135 Montgomery Street, 

 San Francisco, for illustrations of this 

 chapter.) Fig. 9 represents a one-inch 

 focus watchmakers' glass ; price, from 

 75 cents to $1.25 each. Fig. 10 repre- 

 sents a small 

 microscope; 

 l)rice, from .$10 

 to $20. Such 

 i n s t ru ments 

 have sufficient 

 l)()wer for any 

 1 >ractical inves- 

 tigation requir- 

 ed on the farm 

 or its surround- 

 One dozen dass slides, about $1.00: one dozen ghiss 



Fig. 10. 



Fig. 9. 



