FOOD PLANTS OF CITRUS WHITE FLY. 41 
season of the year for their collection, the most successful methods to 
be employed, manner of shipment, and all other factors regulating the 
procedure. A greenhouse could be prepared in Florida, so that there 
would be breeding Aleyrodes on hand at all times of the year. 
As an outline of a second attempt at introducing the natural ene- 
mies of the white fly, the writer would make the following suggestions 
on the basis of his past experience : The work should be carried along 
on a more extensive scale than previously and with the object of 
continuity should the first attempt fail. Two men should be sent 
abroad, to arrive in India by March 1. This would give time for 
adequate preparations before the appearance of the first brood of the 
white fly in April. Several cases such as were used by the writer in 
his expedition should be filled with aleyrodid-inf ested trees and trans- 
ported to India. This would insure a supply of Aleyrodes as well as 
citrus trees should any difficulty be experienced in an attempt to 
secure either on arrival in India. Having collected a supply of nat- 
ural enemies, one of the two men could return with the same to America 
while the second man remained in India carrying out preparations for 
securing material from the second brood of the white fly. Then, if the 
first shipment should prove a failure, no time would be lost in the 
second attempt. Should the first shipment come through success- 
fully, as soon as this was definitely known the agent in India could be 
informed. He could then proceed to the great citrus-fruit-growing 
regions of southern China and endeavor to find other natural enemies 
of the white fly in this little-known region, in which it is quite possible 
the Aleyrodes originated. The writer is very strongly of the opinion 
that in China there should be other natural enemies not found in India. 
FOOD PLANTS OF THE CITRUS WHITE FLY. 
The citrus white fly has attained its great economic importance in 
the United States because of its injurious action to citrus fruit trees. 
Specific consideration of this matter has been given on pages 11-12 of 
this bulletin. It has been stated by Drs. Morrill and Back that in the 
Gulf States oranges of the tangerine group are preferred hosts over 
other varieties of citrus. This same preference was observed by the 
writer in India. Similarly, other varieties of oranges are preferred 
to grapefruit, which was always found highly infested or else free of 
this insect. Lemons and limes appeared to stand intermediate in 
point of infestation between oranges and grapefruit. Some varieties 
of limes were quite as much preferred hosts as oranges. Although 
living specimens of the white fly were usually found on the larger 
leaves of infested plants, because of the greater protection from the 
sun, it is a point of much interest that grapefruit trees were much 
less severely infested than the orange, although in general their larger 
leaves produced a more dense shade than those of the former. 
