48 APPLIED ENTOMOLOGY 



but those consisting of bran or horse manure, poisoned with arsenic or 

 Paris green, and made attractive to the insect by adding strong-smelhng 

 molasses (syrup) and the juice of citrus fruits, have in general been the 

 most successful. Detailed consideration of them will be given in con- 

 nection with the insects for which they are used. 



Hellebore. — This is the powdered roots of the plants Veratrum 

 album and Veratrum viridis. It is a mild stomach poison and can 

 therefore be usad with safety to man, on plants soon to be gathered for 

 food, as it loses its strength quite quickly on exposure to the air. It is 

 sometimes difficult to obtain fresh. 



It may be dusted over the plants, sticking on best if applied while dew 

 is on them, or it may be mixed with from one to three times its bulk of 

 flour or plaster, for this purpose. It may also be used as a spray by 

 steeping an ounce in a quart of water and then adding another quart of 

 water. At the rate of half a pound in 10 gal. of water it is effective against 

 house-fly maggots in manure piles. It is too expensive to use except on a 

 small scale. 



Commercial Sodium Fluorid. — This substance has recently been found 

 to be effective for some insects, acting apparently both as a stomach 

 poison and as a contact insecticide. It is applied as a dust, either 

 pure or mixed in about equal parts, with flour or plaster. Details are 

 given in connection with the insects against which it is used. 



