April, '15] 



ENTOMOLOGISTS' PKOCEEDINGS 



217 



Mr. T. J. Headlee: I think Mr. Richardson can tell us some- 

 thing about this. 



Mr. C. H. Richardson: Experiments were made summer before 

 last in which we found that the young worm was in the apex of the 

 ear within twenty minutes after hatching. These were laboratory 

 experiments. I was not able to prove this in the field as the difficulties 

 of observation were many. There was very little feeding until the 

 worms were within the apex of the ear well hidden in the silk. I think 

 the efficiency depends on a httle of the insecticide deposited on the 

 silks sifting downward as the silks grow out. 



A ^Member : I would like to ask if good results have been obtained 

 with hydrated lime, as we found it was very difficult to prevent a 

 separation of the arsenate of lead and the hydrated lime. 



Mr. J. W. McCollocf: As far as I know hydrated lime has 

 not been used very extensively. The chemical company with which 

 we cooperated this year suggested its use in the place of sulphur. 



Mr. T. J. Headlee: At one time we collected a little evidence 

 on the use of lime as a diluent for powdered arsenate of lead. Gen- 

 erally speaking these tests showed no injury. In some cases, however, 

 the collection of the lime and lead at the axils resulted in the bleaching 

 of the leaf at that point. This was not, however, the universal rule, 

 indicating that the constitution of the lime was variable. As a matter 

 of fact, it is extremely probable that the air-slaked lime used was not 

 yet entirely changed and that the bleaching occurred when the lime 

 was still caustic. The physical nature of lime seems well adapted 

 to serve as a diluent for the powdered lead, but its caustic nature must 

 be changed. 



I should like to ask a question on my own account. I should hke 

 to inquire whether Mr. Haseman or Mr. McColloch have made use 

 of a mechanical distributer of the poisons, and what results they have 

 gotten, if any. 



Mr. Haseman: Would simply say that our machine will powder 

 off — a thin dust. 



Mr. McColloch: We used an ordinary cheesecloth bag. 



Mr. Headlee: I asked that question because in the summer of 

 1913, Mr. Richardson of our department made a thorough test of a 

 horse machine. This distributer was devised by the late Mr. Karl R. 

 Wundt and the speaker and built by the Dust Sprayer Manufacturing 

 Company of Kansas City, Mo. The mixture was delivered as dust 

 under pressure and gave the whole corn plant, especially the ear, a 

 fine coating of the poison. It was tried in Missouri by Mr. Wundt in 

 the summer of 1912 with excellent results. In our test it failed to 

 effect control. A careful study showed that it failed because the young 



