18 FIFTH ANNUAL REPORT 



ECONOMIC IMPORTANCE OF ENTOMOLOGY. 



Man receives some direct benefits from insects, which fact may- 

 be well brought home by taking for example the case of a ylung 

 lady dressing for an evening party: — Her card of invitation is 

 written with ink, the principal ingredient in which — if it is good ink — 

 is the gallic acid made from the so-called "gall-nut" produced by a 

 little gall-fly {Cynips gallce-tinctoricB Oliv.) on the leaves of a species 

 of Oak {Quercus infectorid) very common throughout the Levant. 

 The sealing-wax which fastens the envelope inclosing the invitation is 

 made mainly of shellac, the product of a species of bark-louae ( Coc- 

 cus lacca Kerr) found on various trees, such as the Jujube and Indian 

 fig, in India. Her toilet table is, of course, illumined with wax tapers, 

 and for these she is indebted to the common Honey-bee, {Apis melli- 

 iica)^ a naturalized American citizen. If she is a fashionable young 

 lady, the very rouge on her cheeks is prepared from lac-lake, made 

 either from the bark-louse above mentioned or from the Cochineal. The 

 silk that enters into various portions of her dress comes from the Silk- 

 worm, artificially propagated in many parts of Europe and Asia, and 

 now beginning to attract renewed attention in some parts of our own 

 country. Her dress is probably dyed with cochineal, an extract from 

 the dead bodies of another species of bark-louse ( Coccus cacti Hern.) 

 artificially propagated on cacti in Mexico. Finally, if the young lady 

 contracts some inflammatory cold, the chances are that her physician 

 will apply to her person a blister prepared from cantharides, the dried 

 and powdered bodies of a Spanish blister-beetle, of which we an- 

 nually import large quantities at great expense, because our pharma- 

 ceutists are ignorant of the fact that we have some half-dozen indi- 

 genous species belonging to the same family, the vesicatory properties 

 of some of which are every bit as good, and which are so common 

 during certain years that they are among the most serious enemies of 

 that valuable esculent, the Potato. Indirectly, insects are also of es- 

 sential service to us; some acting as guards over the vegetable world 

 by destroying the herbivorous species of their own Class, some as 

 scavengers in clearing away decaying animal and vegetal matter; 

 while others perform a most important part in the pollenatiou of 

 plants. 



But the direct or indirect benefits we derive from insects are trivial 

 compared with the damage they do us, as destroyers of our crops. It 

 is, therefore, in 



THE RELATION OF INSECTS TO AGRICULTURE, 



That they more particularly interest us. In his essay on "What I 

 Know of Farming," the lamented Horace Greeley says : — 



"If I were to estimate the average loss per annum to the farmers 

 of this country from insects at $100,000,000, 1 should doubtless be far 



