34 report of search for enemies of citrus white fly. 

 Prospaltella lahorensis, the True Internal Parasite. 



It has been -stated in another part of this bulletin that the first 

 definite discovery of parasitic action on Aleyrodes citri was made at 

 Lahore, India. Also it was here that at a later date living material 

 of the parasite was fii'st seen. Wliile no special attempt was made to 

 work out the Ufe liistor}'^ of this insect, numerous observations taken 

 during the summer of 1911 while preparing material for introduction 

 into Florida furnish some definite information on certain points of 

 value. 



Adult parasites could be found at any time between May and 

 November. They were most numerous during the months of May 

 and September. Although found in June, July, and August, they 

 were so scarce that it frequently required several minutes before a 

 single specimen could be located. Moreover, during this time of 

 great heat a large percentage of the parasites died wdthin the host 

 before maturity. As no evidence of hyperparasitism was evident 

 and since this mortahty occurred at all stages of parasite develop- 

 ment, the writer is inclined to attribute this mortality to the effects 

 of the hot dry climate. Observations would lead us to believe that 

 at no time did parasitism of the fly exceed 1 per cent. 



The parasite prefers the larval stages of its host, but when necessary 

 will oviposit in the pupae. Parasitized larvae and pupa3 develop a 

 much greater tliickness than healthy ones. They also soon lose their 

 transparency, becommg opaque, and this renders them easy of detec- 

 tion. By the use of a lens the parasitic larvae, which are of a whitish 

 cast, can be seen within the white-fly host. On reaching the pupal 

 stage the parasite becomes very dark, almost black, so that at this 

 time parasitized white flies containmg pupa cases appear very dark. 

 Having attained maturity the parasite eats a small hole in the dorsum 

 of the host and through this opening emerges into the open air. 



Parasitized Aleyrodes are largely confined to the shadiest part of 

 the plant. The parasite is apparently distributed throughout the 

 citrus-growing region of the Indian Empire. 



Infesting Young Orange Trees with Aleyrodes citri. 



It has been stated under another paragraph that young trees 

 infested with living white flies were necessary for the safe trans- 

 mission of parasites from India to Florida. Since young trees infested 

 with the white fly were not available in that country, infestation was 

 secured in the following way: A large portion of the infested orange 

 hedge at Lahore had been protected by a hea\^ canvas awning. 

 (See PI. VIII.) Under this awning immediately adjacent to the orange 

 hedge, and on the side away from the midday and afternoon sun, was 

 constructed a narrow platform for potted citrus trees. This platform 



