90 
FLORIDA STATE HORTICULTURAL SOCIETY. 
existence in Florida was not unknown to 
the author. The first investigations of 
the Orange White Fly were made by 
Riley and Howard, of the Division of 
Entomology, and the results published in 
1893. The scientific name A ley rodes 
citri was given the insect at this time, 
and its different stages—egg, larval, 
pupal, and adult—were described in de¬ 
tail The subjects of life history and re¬ 
medies were also considered in as thoro 
a manner as the opportunities for the in¬ 
vestigation permitted. The next in¬ 
vestigations of the Citrus White Fly were 
by Dr. H. J. Webber, who, as an agent 
of the Division of Vegetable Physiology 
and Pathology, studiecf the problem from 
the standpoint of the sooty mold which 
follows the attacks of various honey dew 
secreting insects. Of those insects the 
White Fly was recognized as the principal 
pest and in his bulletin published in 1897 
important experimental work with sprays 
was reported and the two most useful fun¬ 
gus diseases of the fly were carefully de¬ 
scribed and their importance discussed in 
some detail. Aside from the reports pub¬ 
lished by the Department of Agriculture, 
the Florida Experiment Station has pub¬ 
lished two valuable bulletins, in addition 
to the records of the observations on the 
White Fly published in annual reports. 
Bulletins on this subject have also' been 
published by the California and Louisiana 
Stations. 
The investigation of the White Fly by 
the United States Department of Agri¬ 
culture was again taken up in July 1906 
as a consequence of the urgent demands 
for such an investigation from Florida 
orange growers. Five thousand dollars 
was appropriated by Congress for this 
work for the first year, ending June 30, 
1907, and for the work of the present 
year $10,000.00 has been available. 
These provisions by Congress have per¬ 
mitted extensive experimental work and 
the detailed results will be published in 
bulletin form from time to time as con¬ 
clusions are reached concerning the vari¬ 
ous phases of the subject of White Fly 
control. My purpose at this time is to 
present a general outline of the scope of 
the investigations at present in progress, 
with a summary of some of the more im¬ 
portant results thus far obtained. 
The paper here presented is based on 
the entire work done in connection with 
the investigation, including that by the 
various men associated with the writer 
during the past two years, more especially 
Messrs. E. A. Back and W. W. Yothers. 
LIFE HISTORY. 
In working out any important problem 
in economic entomology a thoro knowl¬ 
edge of the insect concerned is of prime 
importance. Successful control must take 
advantage of the more vulnerable periods 
in the insect’s life history, while on the 
other hand a knowledge of the insect en¬ 
ables us to avoid useless efforts. Studies 
on the life history of the Citrus White 
Fly extending over a period of nearly two 
years, have reached a point where the 
most important features are well under¬ 
stood. 
During the summer months the eggs 
hatch in from nine to nineteen days, av¬ 
eraging about eleven or twelve days. 
This variation is quite remarkable, inas¬ 
much as eggs deposited upon the same 
day are subject to this wide range in the 
duration of the egg stage. The larval 
stages are even more remarkable in their 
range of variation. Dr. Back has found 
that the larvae hatching from eggs de¬ 
posited in July will reach the adult winged 
