36 FIKST ANNUAL REPORT OF THE STATE ENTOMOLOGIST. 



penetrate them to enter the apples. In subsequent chemical exami- 

 nations of the fruit treated in this manner, no arsenic could be de- 

 tected, and it was freely eaten by Prof. Cook and his family without 

 any injurious effects. Still, additional experiments in this direction 

 are desirable, before we may give to this method of protecting apple 

 trees unqualified recommendation. 



A circular of Hemingway's London Purple Company, 90 Water 

 street, New York, gives the following directions for the use of the 

 purple on potato plants : 



" The best method of use is with water. Mix the purple into a 

 smooth paste, and then add water in the proportion of three gallons 

 to each ounce, or forty-eight gallons to one pound. Stir well, and ap- 

 ply by sprinkling with a whisk or fine watering-pot, taking care not 

 to deluge the plants, but only cover with a fine spray. From an eco- 

 nomical point of view it is wise to pass it through a strainer. This can 

 be done by tying some cheap cotton-cloth over an iron hoop a little 

 larger than the tub or cask in which the mixture is made, the purple 

 put into the strainer and the water poured over it into the cask, which, 

 as it goes through, will leave behind all dirt or bits of sticks which 

 might otherwise choke up the Fountain pump or other spray-produc- 

 ing instrument, 



"If preferred, it maybe used dry in the proportion of six pounds of 

 plaster to one ounce of purple, or 100 pounds of plaster to one pound 

 of purple. Mix well by passing the two materials through a sieve. 

 The more perfectly this is done the more certain the effect. 



" The proportions given above are the strongest that should be 

 used. If care be taken, a much more dilute mixture may be used 

 with equal advantage." 



3. Pyrethrum as an Insecticide. 

 The Persian and the Dalmatian insect powders are the finely pul- 

 verized flowers of species of Pyrethrum — the former of Pyrethrum 

 roseum and P. carneum, and the latter and the most highly esteemed, 

 of P. cineraricB folium. The Persian powder has been known for a 

 number of years, and the peculiar properties of the powder of some 

 species of Pyrethrum had been utilized even in the past century; but 

 until within the last three years, it had only been employed against 

 household insect pests, as flies, mosquitoes, roaches, bed-bugs, etc. A 

 small quantity of it diffused in a closed room by means of the bellows 

 made for the purpose, acts very quickly upon flies, by bringing them 

 to the floor, struggling upon their backs. They are unable to fly, and 

 if placed upon their legs, they are incapable of using them in locomo- 

 tion. The powder appears to produce a paralysis from which they 

 rarely recover, although death may not follow until a day or two there- 

 after. While affecting insects in this manner, it may be distributed in 

 a room as above, and be breathed by persons with perfect safety. 



