86 
FLORIDA STATE HORTICULTURAL SOCIETY. 
ing last summer by spraying or fumigat¬ 
ing 1 and then in winter have undertaken 
to exterminate it by fumigation in the 
citrus trees, and by destroying all of its 
other food plants possible. The injury in 
winter caused by even large overdoses 
of hydrocyanic acid gas would have been 
trivial in comparison to the injury done 
to the trees by cutting off their large 
limbs in order to get rid of the leaves. 
Honey dew Excreted .—Leaves with an 
abundance of whitefly larvae were 
placed between glass plates, and it was 
found that the honeydew ejected by the 
insects was deposited in small drops on 
the glass above or below them, in some 
instances the liquid being precipitated up¬ 
ward a distance of 1-8 inch or more. Pu¬ 
pae ready to have the adult emerge se¬ 
crete honeydew as well as larvae of all 
stages. A lot of larvae of perhaps the 
third and fourth stages of growth ex¬ 
creted at the rate of .0005 gram each in 48 
hours. At this rate 1,000,000 larvae (in 
round numbers) could excrete one pound 
of honeydew in 48 hours, which would be 
at the rate of 15 pounds per month or 
180 pounds per year. Since no doubt a 
large percentage of this sweet excretion 
is sugar (let us assume 50 per cent., 
since we have not had an opportunity 
to test it or have it tested), at this rate 
100 trees of good size on an acre of 
ground would lose something like 50 
barrels of sugar per year, allowing 1,- 
000,000 whitefly larvae to a tree. These 
50 barrels are the equivalent of 10,000 
pounds, or 5 tons; at 5 cents per pound, 
this would amount to $500.00. Of 
course, this is not the actual loss per 
acre, since carbon, hydrogen and oxygen, 
the components of sugar, come from 
the air; but it does represent an unneces¬ 
sary amount of work that the trees are 
required to do, granting that they bear 
a full crop besides, which they probably 
never do. This great amount of loss of 
sugar and water, however, does account 
for the insipid and dry fruit of whitefly- 
infested trees, and suggests the necessity 
of giving the trees an extra allowance 
of fertilizer and, of course, sufficient wa¬ 
ter. 
Two Species .—Are there two species 
of white fly seriously affecting the citrus 
trees in Florida? The writer has several 
times observed that the eggs of the white¬ 
fly in certain localities in Florida had a 
different appearance from those in other 
localities. Last fall and winter, while 
Prof. H. S. Fawcett and Mr. R. Y. Win¬ 
ters were doing some work with the mi¬ 
croscope under the writer’s direction on 
the whitefly larvae and eggs, our atten¬ 
tion became further directed to a peculiar 
delicate net-like covering to certain eggs. 
After examining material from different 
localities, I found that only whitefly 
eggs from certain localities had this cov¬ 
ering, eggs from other localities being 
perfectly smooth and shiny. A like ex¬ 
amination of eggs of this spring’s brood 
from the same localities revealed the 
same differences, together with decided 
differences in the external structure of 
the larvae of the first stage. At the 
time of writing this no literature on the 
whitefly has been found which takes 
note of differences such as have just been 
stated. 
It is true that Professor H. A. Morgan 
in his bulletin (previously cited) figures 
the reticulated type of egg for the white¬ 
fly in Louisiana in 1893, and in his de¬ 
scription of the egg mentions “a film-like 
covering arranged in hexagons—;” but 
it is evident that he was not aware of the 
existence of two types of eggs represent- 
