POSSIBLE EFFICIENCY OF ENEMIES IN FLOEIDA. 39 
conditions in India and from the fact, as he had there determined, 
that both the parasitic and predaceous enemies of the white fly pass 
through considerable periods of hibernation, both in the winter season 
and in the dry season, it seemed to him that the best chance of success 
was to allow the imported material to go through the winter in a nor- 
mal condition of hibernation. The alternative was artificially to 
force, throughout the whiter, active breeding of these imported 
insects and of the white flies as hosts. 
With the exception of a small number of the more active specimens 
of the lady-beetle enemy of the white fly, an attempt was made to 
carry the imported insects through the winter in a state of hiberna- 
tion, with the unfortunate result that none of the parasites or of the 
lady-beetle enemy of the white fly survived. 
The small number of more active ladybird beetles referred to were 
removed from the Wardian cases in which they had been imported 
and taken into the laboratory and placed on young trees infested with 
white flies in the dormant, pupal stage. The white fly hi this stage 
was not well suited to them as food, which is by preference the egg 
and early larval stages, and by the 1st of January all but two of the 
beetles taken into the laboratory had perished. About the middle 
of January eggs were obtained from white flies reared in the warm 
room and the two remaining beetles were removed to a small potted 
seedling orange tree stocked with such eggs. The feeding of these 
beetles on the eggs was voracious and they remained alive through 
the whiter but as they were apparently of the same sex they died 
without reproducing. 
The loss of the parasites and the ladybird enemies of the white fly 
is very regrettable. Possibly such loss can be avoided, if another 
importation is made at the same period, by adopting the method of 
keeping the insect enemies and host insects in active breeding through- 
out the winter in a suitably constructed and well-stocked greenhouse. 
Possibly an even better chance of success will come from importations 
so timed as to arrive in early summer. 
THE POSSIBLE EFFICIENCY OF THESE NATURAL ENEMIES IF 
ESTABLISHED IN FLORIDA. 
Considering the comparative weather conditions of Florida and the 
parts of India infested with the white fly, the writer sees no reason 
why Prospaltella laliorensis and Cryptognatha flavescens could not be 
successfully established in this country. 
It has already been stated that neither of the two natural enemies 
of the white fly exerts any great effect in controlling the white fly in 
India. The great natural enemy of the white fly in that country is 
the excessive heat, and this very element which limits the mjuriousness 
of the white fly is, in the writer's opinion, largely the one that keeps 
