72 . 



Results. — In 5^ minutes after fumigation commenced beetles on the 

 plants dropped, and those on the surface rolled over and drew them- 

 selves together, apparently dead. About one hour after fumigation 

 they all recovered. 



EXPERIMENT V. 



Conditions. — Glass box; darkness; same as above except that time 

 of exposure was 25 minutes. 

 Results. — Same as in Xo. IT. 



EXPERIMENT VI. 



Conditions. — Made November 29, 1897; darkness; 1 oz. potassium 

 cyanide, 1 oz. water, If oz. acid to 112 cu. ft. (see table); plants: cine- 

 rarias (1 sprinkled with water, 1 dry), smilax (1 sprinkled, 1 dry), 

 ferns; insects: rose beetles; time, 25 minutes. 



Results. — Plants not at all injured; nearly all beetles killed. 



To destroy the rose beetle it will probably be better to use less 

 strength of gas and place sheets of paper or canvas beneath the plant 

 infested, than to use the larger percentage of cyanide, as they are sure 

 to drop off when the house is fumigated with sufficient strength of the 

 gas to kill mealy bugs. They can then be gathered up and destroyed. 



TRIAL III. 



Conditions. — Date, Xovember 27, 1897; place, rose room; 1 oz. potas- 

 sium cyanide, If oz. acid, and 1 oz. water to 570 cu. ft.; room contained 

 only roses, the new shoots being covered with green f y ; length of time 

 fumigated 25 minutes (see table). 



Results. — All aphides were killed, but the tender buds and leaves of 

 the plants were injured. 



TRIAL IV. 



Conditions. — Time, November 29, 1897; place, octagon room; 1 oz. 

 potassium cyanide, 1 oz. water, 1 oz. sulphuric acid to 175 cu. ft. 

 (see table). In this room, containing 25,689 cu. ft. of space, three jars 

 were used with 49 oz. of cyanide to each jar. In this room was a large 

 number of tropical plants, trees, and ferns. It was very badly infested 

 with mealy bugs and scale, beetles, and aphides. 



Results. — Very satisfactory; many of the beetles dropped on the 

 walk and died. The only injury noted on December 20 was on the 

 climbing Perle des Jardins rose, but this was not serious. The tree 

 fern, which was very badly infested with mealy bugs, has sent out several 

 new fronds. The manettia vine, which had its growth checked by mealy 

 bugs, now has long growing shoots and is covered with blossoms. In 

 fact, all the plants in this room have made new and decided growth. 



trial v. 



Conditions. — Place, camellia room; 1 oz. potassium cyanide, 2 oz. 

 water, and 1 oz. sulphuric acid to 190 cu. ft. (see table); insects 



