INSECT POWDER 51 
of pollen and the absence of fruit tissues indicate closed flowers; 
And, conversely, the absence of much pollen and the presence of a 
large amount of fruit tissues indicate open flowers. These tissues 
are very characteristic and can not be mistaken (PI. IV). 
2. Mixtures of flowers and stems are made up on the basis of 
lowest cost. By following the market prices on closed and open 
flowers and stems, the analyst can usually tell which has been used 
in preparing a mixture of flowers and stems. 
3. From the intensity of the green color of the ether extract, 
after if: little experience, the amount of stems present can be told 
roughly. 
ae The crude fiber determination, taken in connection with the 
intensity of the green color of the ether extract, general appearance 
of the powder, and odor, serves as a good indicator as to whether 
or not the mixture is composed of open flowers and stems or closed 
flowers and stems. 
By a combination of all of these tests, but more particularly by 
microscopical examination, it is possible to tell whether closed or 
open flowers have been used in a mixture, and, by the use of the 
formula, to determine the approximate percentage amount of flowers 
and stems present. 
In Table 37 are given the nitrogen and phosphorus pentoxid con- 
tents of 10 known mixtures of open flowers with stems, and the 
pen uey of stems calculated from each of these values, using the 
ormulas just given. 
TABLE 37.—WNitrogen and phosphorus pentoxid content of known mixtures of open 
flowers and stems and quantity of stems present 
Stems calculated 
from— 
Sample No. Stems eee PiOp) es oe Means | Enron 
Per cent | Per cent | Per cent | Per cent | Per cent | Per cent | Per cent 
0 1. 280 0. 3 1 2 
isp Se Ss Soe a 530 + 2 
eis Doe ee ey eee eae 0 1, 23 . 623 6 3 5 + 5 
Dee ee eee oe Se 0 1. 250 . 510 3 7 5 ap 
Bier Sree wR Se 10 1. 185 . 459 16 24 20 +10 
Ti SS oe See ee ee ee 10 1.170 . 482 19 17 18 + 8 
De Bee Tes ioe oe es ee ae 20 1. 140 . 411 25 40 33 +13 
ee ee en See ae RIS yaa) eso 20 1.170 . 447 19 28 24 + 4 
(oasis os el ee a ey ae i 60 1. 035 . 275 46 86 66 Gs 
a eee a os 60 919 . 300 70 77 74 +14 
LU pa ae ge ey 80 947 . 206 64 100 82 + 2 
Tables 38 and 39 give the results of the analysis of commercial 
insect powders. Those reported in Table 38 are on the samples 
unadulterated with stems, foreign plant material, or coloring matter, 
while those in Table 39 are on Samples adulterated with ground 
Pyrethrum stems, sand, chromates, or other materials. 
