319 



with water to tbe desired proportions." lu the proportion of 1 part of 

 the emulsion to 450 or 500 parts of water the mixture was found to be 

 sufficiently strong to destroy the worms. "The extract kills entirely by 

 contact. It makes the cotton worms uneasy as soon as applied and 

 causes them to drop to the ground writhing in great agony. This con- 

 tinues until they become greatly exhausted, when they often remain 

 motionless for some time before death. While the emulsion is so de- 

 structive to insect life, it is not in the least injurious to those handling 

 it." As usod at the station 1 gallon of the extract cost G5 cents and 1 

 pound of soap 10 cents. When this is diluted with 450 gallons of water 

 it gives a sufficient quantity of the mixture to spray 15 acres of cotton 

 at a cost of about 5 cents per acre. 



Several experiments in which the kerosene extract was combined 

 with wood or coal ashes, cotton-seed meal, or flour, and ajiplied in a dry 

 form, are briefly reported. The most satisfactory results were obtained 

 when the mixture was combined in the proportion of five eighths of a 

 pint of the extract to 1 pound of wood ashes, but the author is not yet 

 prepared to recommend the use of this insecticide in a dry form. 



Dry mixtures were also prepared by combining 1 iiound of flour 

 with the following quantities of each of the several substances named : 

 siintonin (1 ounce), oxalic acid (8 ounces), benzoic acid (1 ounce), mer- 

 curic chloride (2 ounces), tartar emetic (1 ounce), salicylic acid (1 ounce), 

 ciuchonin (1 ounce), bichromate of potash (8 ounces), hellebore (amount 

 not stated), lead acetate (8 ounces), and veratrin {^ ounce). The vera- 

 trin was by far the most satisfactory in its action. It killed the insects 

 by contact and when they ate it. This insecticide is about as expen- 

 sive as Paris green. 



Observations in the field indicated that the numbers of the cotton 

 worm were diminished by the following enemies: Blackbirds, ants, 

 spined soldier bug {Fodmis spiiiosus), dusky plant bug {Derccocoris 

 rapidus), a species of Fanorpa, Trichogramma xjretiosa, Chalcis oratus, 

 and Enplectrus comstoeJdi. 



Colorado Station, Bulletin No. 12, July, 1890 (pp. 151). 



Some Colorado grasses, and their chemical analysis, J. 

 Cassidy, B. S., and D. O'Brine, D. Sc. (illustrated). — In a brief in- 

 troduction the director of the station states that " this bulletin is the 

 result of work undertaken early in 1889 by the experiment station, to 

 study the grasses of the arid region, and more particularly of Colorado, 

 in order to find, if possible, some varieties which would furnish more 

 and better forage than those now cultivated. The chemical work was 

 undertaken to show the comparison in composition of these species as 

 grown in their native habitat and afterward under cultivation ; first, 

 without irrigation, and second, under irrigation. The botanical work 

 has been almost exclusively performed by our late Professor James 

 Cassidy, and the chemical work by Dr. David O'Brine, chemist." 

 18447— No. 7 2 



