22 



this point I have observed them carefully and examined with partic- 

 ular care the grass blades on which I have seen them established. 



On September 7, 18S9, I swept grass where no other living plants 

 were to be seen and collected numerous Hemiptera of a number of dif- 

 ferent species, mostly Homoptera. The grass was very dry, brown, and 

 in many places appearing dead, but evidently still furnishing support 

 for the leaf-hoppers. There were but few other insects present, scarcely 

 any that could be supposed to feed upon grass, except some grasshop- 

 pers (Galoptenus femur-nibrum, species of (Edipoda, etc.). The species 

 of Homoptera collected may I think be considered as unquestionably 

 grass feeders. ^No other vegetation that could furnish them support 

 had been on the ground swept for weeks, and the insects swarmed on 

 every square foot. The grass commenced turning brown in patches 

 long before it should be expected to, if affected only by want of rain, as 

 it showed within a short time after the last rains, which had been quite 

 regular and copious, previous to the dry period of that time, and its dry- 

 ing up must have been hastened by losses due to the presence of in- 

 sects. The ground was not yet dry enough so that the grass could 

 have suffered from lack of moisture alone. Their presence on grass 

 seems to show its effect in two ways, though for one of them it is diffi- 

 cult to draw the line between the effects of leaf-hoppers and dryness. 

 In one the effect of punctures shows in numerous pale and dry spots on 

 the blades of grass resembling effects produced by related Homoptera 

 on other plants, apple-trees, pear-trees, grape-vines, etc. Such spots 

 can not be found, however, in such numbers as would be expected if 

 there were one for every puncture by the millions of these insects that 

 occur in every piece of grass land. But the great bulk of the grass is 

 withered or dead down to a certain point near the ground (or to the 

 ground), which would naturally be the appearance if the leaf withered 

 from the lower punctures to the tip, thus obliterating all punctured 

 spots on the terminal portion. 



The difference between grass withering from punctures and from lack 

 of moisture is perhaps not sufficiently different to furnish a very safe 

 basis for deduction, but in the latter case it is naturally more gradual 

 and holds for a longer time the green color of hay, so that for withered 

 grass not too long exposed I believe we should be able to distinguish in 

 some degree the difference between that killed by leaf-hoppers and that 

 dried by excessive heat and lack of moisture in the ground. 



While this may fall short of actual demonstration, I think a careful 

 study of the effects in the field will convince any one that my conclusions 

 are justified by the facts and that, taking year after year, the amount of 

 injury caused by insects of various kinds is fully equal to the amount 

 consumed by the stock ordinarily pastured on the same land. It is evi- 

 dent, then, that the prevention or the reduction of the insect injuries 

 would add an equivalent amount to the return from such land. Instead 

 of one cow requiring two acres for pasturage,pastures comparatively free 



