260 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



The effective temperature of the soil seemed to be between 60° and 

 65° F., for when it was colder than this they did not move in the soil, 

 did not feed, and scarcely made any resistance to handling. 



2. Their food was found to consist, so far as observed, of the roots 

 of plants only, or the fragments of these roots. They were never 

 seen eating or manifesting any interest in any form of sweetened 

 bran, dough or flour paste. In sprouting seed they uniformly ate 

 the radicle and left the caulicle unharmed. This is also apparently 

 true in the case of strawberries in the field, even when they have been 

 planted so deeply as to cover the petioles of the leaves. In the case 

 of grass it is more difficult to be certain of this habit. 



3. Grubs were reared in flower pots containing moist garden soil 

 with no apparent food from May 5 to July 18; the soil was then 

 allowed to dry and on the 22d of October two larvae were still found 

 emaciated but alive and active in soil almost completely desiccated. 

 The grubs then succeeded in living on minute root fragments and 

 other humus in the soil for five and one-half months, of which the last 

 three were passed in almost bone-dry surroundings. Under these 

 circumstances, starvation methods of controlling them are proven 

 impracticable. 



4. Poison bran mash was found to be valueless against the grubs 

 whether drilled into the earth above or below the larvse or placed on its 

 surface. This is, of course, due to the fact that they will not eat the 

 bran, 



5. In several experiments, including about forty grubs, grass roots 

 were shaken free from earth, dipped in various arsenicals, and planted, 

 in an attempt at poisoning the grubs. The use of sodium arsenite 

 in this way, in the proportion of five pounds to fifty-four gallons of 

 water, resulted in killing six larvse out of a total of twenty-seven 

 subject to poisoning, a mortality of 22.2 per cent in four days. No 

 injury to the grass was observed. Attempts to accomplish the same 

 results with lead arsenate in the proportion of five pounds of the 

 paste to fifty gallons of water were unsuccessful. Corrosive sublimate 

 used in the same way on a small corn plant caused a mortality of 

 50 per cent, but not in time to save the plant, as the roots were entirely 

 eaten away by the grubs. 



6. Kerosene emulsion and Black Leaf "40," in their ordinary 

 strengths, did not affect the larvse in the least when the soil was 

 saturated with these solutions. 



7. Professor H. T. Fernald a few years ago reported the successful 

 use for two seasons of a repellant of tar on seed corn in preventing 

 the attack of wireworms. Several repellants were tried in the experi- 

 ments here being reported, but the only one which did not injure the 



