142 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



ticated in so far as it occurs mostly about habitations. In conversation 

 he has informed me that he didn't find that species in the upper Chagres 

 River, where there were no habitations. It seems on the other hand, 

 that the species which occur in the wild play no part in the transmis- 

 sion of malaria, — rather a curious fact. (See p. 196 for a more extended 

 discussion of this phase. — Ed.) 



President F. L. Washburn: The next paper on the programme 

 is by Mr. Yothers, of Orlando, Florida. 



INSECTICIDES FOR USE IN CONTROLLING THE WHITE FLY 



By W. W. Yothers, Orlando, Fla. 

 {Withdrawn for publication elsewhere) 



Mr. Berger: Mr. President, we believe in Florida that these 

 formulas, that Mr. Yothers has invented, are a decided advance in 

 the matter of the application of oils. They have, of course, so far, 

 been applied to citrus trees which are evergreen, and the suggestion 

 that is foremost in my mind here, is the possible usefulness of these 

 insecticides or spraying solutions in the North on trees in full foliage. 

 I might add that a prominent nurseryman in Florida, who grows 

 ornamentals, is using formula 4 and experimenting with it in the 

 greenhouse, with apparent success. The use of these mixtures on 

 other plants besides citrus is of course, in the experimental stage, but 

 the outlook is promising. 



President F. L. Washburn: Any other member who wishes to 

 discuss this paper? If not we will pass to the next paper, by Mr. R. A. 

 Cooley, of Montana, on "Orthoarsenite of Zinc as an Insecticide." 



ORTHO ARSENITE OF ZINC AS AN INSECTICIDE 



By R. A. Cooley, Montana Agricultural Experiment Station 



During the past two seasons the Montana Experiment Station has 

 had opportunity to experiment with the insectitude furnished by the 

 California Spray-Chemical Company, called ortho arsenite of zinc, 

 Two lots of the chemical have been used, one received in May 1910 

 and one in May 1911. Our observations have been concerned with 

 its suspension qualities, injuriousness to the bark of the apple tree,, 

 and killing power with insects. 



This ortho arsenite of zinc is a very finely divided, white, fluffy 

 powder, a given weight occupying about four and one-half times the 

 space of Paris green. If first rubbed into a paste with a small amount 

 of water, it mixes well in proper dilutions for spraying. 



