98 TRANSACTIONS OF THE ILLINOIS 



interested but impotent spectator, whilst the conservative and almost 

 invisible agencies of nature have moved silently forward to their benefi- 

 cent consumation. 



We have time to refer to but one more species of noxious insects, and 

 that shall be — 



Fifth — The Colorado Potato Beetle. It is a well known fact that 

 almost all our injurious insects have come from the East, and many of 

 the most destructive of them have been imported from the other side of 

 the Atlantic. This is readily explained by the circumstance that the tide 

 of emigration has set from east to west, and injurious insects have followed 

 in its wake, increasing in numbers in proportion to the extent to which 

 those crops upon which they respectively depredate, have been cultivated. 

 The Colorado potato beetle is the only insect of a serious character which 

 has come to us from the West. The destructive grasshopper of the west- 

 ern plains is also an originally and exclusively western species, but it has 

 never yet crossed the Mississippi river. The Colorado beetle stands alone 

 in the suddenness of its advent, the rapidity of its spread, the uniform 

 persistency of its operations, and the totality of its destructiveness to the 

 crop upon which it feeds. In the last respect it stands in the same cate- 

 gory with the plum curculio. When unresisted it takes the whole crop. 

 We cannot afford to do here as we do in many other cases, let things 

 have their own course, and content ourselves with taking what our insect 

 enemies leave; for the potato beetle leaves nothing but the stubs of the 

 vines. The farmer, therefore, is compelled to give to this insect his very 

 particular attention, and to resist it with all his forces, and all his inge- 

 nuity, or else abandon the crop. It is unnecessary here to enumerate all 

 the devices which have been employed to destroy this insect. They have 

 all been for the most part superseded by the use of the Paris green ; and 

 since it has been found that this article can be used about as effectually 

 in the liquid as in the; powdered form, the most serious objections to its 

 use have been obviated. 



In their march eastward these insects have reached many of the 

 western counties of New York, Pennsylvania and West Virginia, and they 

 were found in considerable numbers, the past summer, in one locality in 

 the District of Columbia. The reports as to their prevalence in the 

 Western States, in the present year, have been very much as in the two 

 preceding years, very conflicting, or rather very serious in different locali- 

 ties. It is evident that they must yet be regarded as noxious insects of 

 the most serious character. 



The natural agencies to which we can often look with confidence 

 to relieve us from the inflictions of noxious insects, seem to make but 

 little impression upon these unwelcome visitants from Colorado. Thick- 

 skinned, stolid, imperturbable, and doggedly persevering, they seem 

 determined to fight it out upon the line which they have adopted, though 

 it may take, not one only, but many summers. The intense mid-day sun 

 sometimes scorches them to death when they chance to get knocked down 

 upon the burning sand ; the lady bugs nip them in the bud by devouring 

 their eggs ; the Anna spinosa impales them upon its spear ; the Tachina 



