EXPEEIMEXT STATIOJT EEPORT. 545 



poured into tlie holes once or twice a day, until no moro cutei^ 

 pillars are in the ditch or furrow. 



. Having isolated the infested area, if the plants are com, they 

 may be heavily sprayed with arsenate of lead, one pound to ten 

 gallons of water, to kill the caterpillars feeding on them. Arsenate 

 of lead is recommended because it may be used very strong witbc^ift 

 causing injury to the plants, but Paris green, one pound in on© 

 hundred gallons of water, will answer as well, exccpti that it will 

 burn the leaves to a greater or less extent. Spraying wheat, millet 

 or other narrow-leafed grasses with arsenites is not recommended^ 

 because of the dijESculty in making the material stick, but kerosene 

 may bei used to good advantage if the crop is so far gone as to be 

 valueless. 



If the cater]ullars are less than two-thirds grown, advantage 

 may be taken of their fondness for bran, and dry bran mixed witti 

 white arsenic, at the rat© of one pound of arsenic tO' fifty pounds 

 of bran, may be scatteired liberally over the ground or among the 

 plants. Paris green, at the rate of one pound to twenty-five pounds 

 of bran, will do as well. Most of the caterpillars tend to get down 

 from the plants during the middle of the day, and will find the 

 bran before they climb for another meal. Where a brood is- dm- 

 covered early, this poisoned bran treatment may be all ihsi is 

 necessary. Where the insects are not discovered until they have- 

 begun to spread, the first thought should be to limit them by the 

 furrow as already descril)ed. 



Natural £neinie«. 



It has been stated that the caterpillars tliis year were unusuallV 

 free from parasites. This statement is based partly upon the labo- 

 ratory results and partly upon the fact that no eggs of Nemoraea- 

 leucan(ice Kirkp., werei noted on them. This Nemmuea leuemmce--- 

 is a good-sized bluish fly, soimething like the ordinary blue-bottle in 

 appearance, and it lays its white eggs on the back of the caterf>i]]ar 

 just behind the jaws or legs. These eggs are easily visible and their- 

 practical absence this year indicates a very heavy brood of late 

 adults and may mean danger next year. 



In the ditches a few examples of caterpillar hunters — Targe 

 predatory beetles of the genus Calosoma — were observed, but not ii6 

 sufficient numbers to have any perceptible effect in reducing the 

 number of "worms." 



35 



