April, '10] WASIIBrUX : EMPOASCA AND PAPAirEMA ]67 



it was only fourteen feet in actual distance from the starting point. 

 Another larva traveled a distance of fifty-six feet before becoming 

 exhausted and at that time was only sixteen and one-half feet from 

 its starting point; a third traveled a total distance of fifty-five feet, 

 and ended twenty-four feet from the starting point, this being the 

 farthest distance reached from the starting point of which we have 

 record. These larvae were all practically full grown. Occasionally 

 ants appeared to attack the larva? and cause considerable annoyance. 



Plants, the lower part of whose stems were covered with tangle- 

 foot, were completely exempt from injury. It was repeatedly ob- 

 served in these experiments that when a larva got within a foot or 

 two of a food plant, it had to be constantly turned away from it, since 

 it showed great determination to reach the stems of the desired plant. 

 The two charts shown illustrate the devious routes of two of these 

 larvae. In one it will be noted that a fairly straight course was taken 

 through plot 46, filled with tomatoes. This was undoubtedly brought 

 about by the fact that although it sought to enter the tomatoes, it 

 was kept away from them constantly, hence the somewhat straight 

 course through that plot. Each plot as shown was four feet square, 

 and the space between the plots was four feet. 



The parks about Minneapolis and St. Paul are kept remarkably 

 clean and free from weeds, and several days spent in examining 

 flower beds in these parks resulted in finding that they were almost 

 entirely free from the attacks of stalk borers. When these pests were 

 present they were always found in beds located in a neglected corner 

 of the park near some weedy patch, it being evident in these cases that 

 the larva^ came from the weeds. 



Economic Suggestions and Experiments : It is very evident that 

 where flower gardens and their environment can be kept perfectly 

 free from weeds, freedom from attacks of this pest is assured. From 

 our own observation it is clear that it is very desirable to clear up 

 weeds that start during the latter part of May and during June in 

 such places, because at that time any young larv® which may be min- 

 ing the leaves of the weeds, will be destroyed with the weeds. Further, 

 it is not probable, from what we have seen in our own experimental 

 garden, that these pests make extensive migrations to other plants. 

 Occasions arise, however, when an owner of a garden cannot control 

 adjoining ground, which may be weedy, in which case it is necessary 

 to find some means of keeping the larvae out of the garden entirely. 

 Without going into details of the experiments which we have tried 

 this last summer, experiments which called for the planting of very 



