183 



a tube so that kerosene may be drawa from one receptacle and a mix- 

 ture of soap and water from another, thus forming a mechanical mixture 

 in the act of spraying. This modification, at the request of Professor 

 Henry, I have had tried in this series of experiments, and although it 

 is too early to state the results, it may be said that so little time and 

 labor are required in preparing a stable emulsion that this mechanical 

 substitute will probably not come into general use. In^this connection 

 it may be observed that the formulfe recommended by some of our most 

 voluminous writers are very misleading, and are calculated to produce 

 only a mechanical mixture more or less unstable. The use of kerosene 

 temporarily combined with water or soapsuds by mechanical means 

 dates from many years back ; it was a favorite remedy of my friend 

 Thomas Meehan, who urged it in 1871 in the Gardener's Monthly ; it was 

 experimented with by others, and 1 used it successfully in 1872 against 

 an undescribed Lecanium on Austrian pine, as also against Aphides on 

 the place of Mr. Julius Pitman, of St. Louis, and in 1874 and 1875 

 against the congiegated young of the Eocky Mountain locust. But 

 the true and stable kerosene emulsion, which now forms one of the 

 most satisfactory and widely used insecticides, and which requires two 

 parts of the oil to one of the emulsifying agent, violently churned until 

 a stable, butter-like emulsion results, was the outgrowth of my eftbrts 

 in the investigation of the Cotton Worm, the milk having been first sug- 

 gested in 1878 by the late Dr. W. S. Barnard while working at Selma, 

 Ala., and the most satisfactory formula in 1880, from experiments which 

 I had continued over two years by Mr. H. G. Hubbard on orange trees. 



A locust outbreak of some interest has occurred in parts cf Idaho and 

 Utah and has been investigated by Mr. Bruner, the l!^ebraska agent of 

 the Division. The species involved proved to be Camnula yellucida, which 

 has overrun the strip of country 140 miles in length by from 15 to 30 

 in width, commencing at a point about 30 miles westward of Soldier, 

 Idaho, and extending east as far as East River and Birch Creek. The 

 people in these sections are quite willing to do whatever can be done to 

 destroy these insects ; but they need instruction. The country has been 

 largely settled since the publication of the early reports of the TJ. S. 

 Entomological Commission and the new settlers lack experience in deal- 

 ing with locusts; for fifteen years make great changes in the rapidly 

 growing West. I have, therefore, in preparation a bulletin treating of 

 the several species of locusts which are responsible for these frequent 

 scares and which will include, at the same time, a summary of the prac- 

 tical portions of the earlier reports of the Entomological Commission on 

 Caloptenus spretus, long since out of print. 



The Army Worm proved injurious in several localities during the past 

 year, particularly in Maryland and Indiana. The Maryland occurrence 

 is of considerable interest, owing to the fact that the preceding year 

 was one of unusual precipitation throughout the Atlantic States, though 

 with some remarkable local exceptions. Indeed one of the parties who 



