572 General Notes, [July, 
open, or at the time when fertilization takes place, as the essential oil 
that gives the insecticide qualities reaches, at this time, its greatest 
development. When the blossoming has ceased the stalks may 
be cut within about four inches from the ground and utilized, be- 
ing ground and mixed with the flowers in the proportion of one 
third of their weight. Great care must be taken not to expose 
the flowers to moisture, or the rays of the sun, or still less to 
artificial heat. They should be dried under cover and hermeti- 
cally closed up in sacs or other vessels to prevent untimely pul- 
verization. The finer the flower-heads are pulverized the more 
effectually the powder acts and the more economical is its use. 
Proper pulverization in large quantities is best done by those who 
make a business of it and have special mill facilities. Lehn & 
Fink, of New York, have furnished us with the most satisfactory 
powder. For his own use the farmer can pulverize smaller quan- 
tities by the simple method of pounding the flowers in a mortar. 
It is necessary that the mortar be closed, and a piece of leather 
through which the pestle moves, such as is generally used in pul- 
verizing pharmaceutic substances in a laboratory, will answer. 
The quantity to be pulverized should not exceed one pound at a 
time, thus avoiding too high a degree of heat, which would be 
injurious to the quality of the powder. The pulverization being 
deemed sufficient, the substance is sifted through a silk sieve, 
and then the remainder, with a new addition of flowers, is put 19 
the mortar and pulverized again. ; 
The best vessels for keeping the powder are fruit jars with patent 
covers or any other perfectly tight glass vessel or tin box. 
In the next number we will give some account of the different 
ways in which the powder may be used to destroy insects. 
TREES ATTRACTIVE TO BuTTerFLiss.—Mrs, A. E. Bush, of San 
José, Cal., writes: “I have been to Monterey, and was on 
enough to see the ‘butterfly tree,’ or trees, as there are three © 
them. These trees are the Monterey pine (Pinus insignis Dougl.), 
and are probably over one and a half feet in diameter, and coml- 
pletely covered with live butterflies. To say that there were as 
many butterflies as leaves upon the trees would not bea pot“ 
great exaggeration. I saw them in the morning when it was coo! 
and they could not fly very well, and picked up a dozen from the 
grass in a few seconds, A lady resident informed me that for the 
twelve years she had lived there the appearance had been the 
same.’ . 
belonging to ten genera, all the genera but one occurrin ret 
Great Britain. The list includes Vanessa antiopa, Pyramets ¢ 
