PRACTICAL TREATMENT — SCIENTIFIC TERMS. 21 



NUMBER MORE IMPORTANT THAN SIZE. 



II is worthy of remark that by far the greabn- inoportion of tlie 

 (laina^c (caused by injurious insects is ett'octed by spiM-ies oC very small 

 size, whilst the hirge sjjecies are j>enerally harmless. The two niosl, 

 serious fruit insects, the (.'odliug-inotli and the i'hnn curculio, are botii 

 l)('h)W the medium size, and the Appk^- bark-louse, the Ap|)leaphis, the 

 licssiau-lly, and the Wheat niid^c, are so minute that (hey would not 

 be noticeable were it not for the wide destruction which they cause to 

 some of our most valuable crops, in consequence of their excessive mul- 

 tiplication. 



TREATMENT OF INJURIOUS INSECTS. 

 For the tletails of treatment the reader is' referred to tlir jtractical 

 treatises and rei)orts which liavebeen ])ub1ished ujKin this siil»j«'ct. We 

 can give here only an abstract of the methods to be pursued. 



First, hand-picking and destruc'tion by machinery, as in the case of 

 the Coloratlo j>otat()-be(^tle ; second, poisoning l)y such substances as 

 Paris-green, hellebore, and carbolic acid, as in the cases of the Potato- 

 beetle, and the Currant saw-fly ; third, rendering their food distasteful 

 jind repugnant to them by the ai)pli('ation of such substances as ashes, 

 lime, and whale-oil soap, which are applicable to all foliage-eating in- 

 sects ; fourth, anticipating their attacks by planting at such times as 

 will cause the crops to sprout or to mature too early or too late for them, 

 both of which plans are exemplitied by winter wheat, in its relation to 

 the Ohinch-bug and the Hessian-fly; and hfth, when all other means 

 fail, preventing their ravages by abstaining for a year or two from rais- 

 ing the damaged crops. To these may be added, in certain favorable 

 instances, the transportation and colonization of friendly parasites. 

 An experiment of this kind has been performed by the author by the 

 transiKirtation from the central to the northern i)arts of the State of 

 Illinois, of the minute Chalcis-fly, which is parasitic upon the Oyster- 

 shell Bark-h)use. 



The above list exhibits the most common methods of contending with 

 injuricms insects, and these methods admit of ahnost indefinite moditi- 

 caiioii. Hut they can be mt)st usefully described in connection with the 

 l)articular species of insect to which they are respectively applicable. 



USE OF LEARNED AND SCIENTIFIC TERMS. 



With regard to the use of scien title terms, derived mostly from the 

 Greek and Latin languages, it is to be remarked that though they may 

 a[>pear ditticult and forbidding, at first sight, the student soon becomes 

 familiarized with them, and iinds them to be almost indisi)ensable by 

 enabling him often to express in one or two words what would require a 



