INSECT CONTROL 315 



charges had reached Florida alive ; a second shipment 

 also resulted in failure. Undismayed by this contretemps, 

 Mr Woglum proceeded to Lahore, where he also found the 

 white fly, though, once more, not in sufficient quantity to 

 be a serious pest. Examination of the infested leaves 

 showed that some of the pupa cases were abnormally 

 thickened and they were always pierced by a small round 

 hole. It was surmised, and correctly so, that a hymenop- 

 terous parasite had been at work. Material was collected 

 and sent to Washington, where it was found that the 

 parasite was a member of the genus Prospaltella, new to 

 science, so it was named, after its native home, Prospaltella 

 lahorensis. Further travels in India by this intrepid 

 entomologist forced him to the conclusion that the citrus 

 white fly is distributed throughout that country south of 

 the Himalaya Mountains, and that evidences of parasitism 

 were everywhere apparent. 



In the spring of 1911 a second visit was made to Lahore, 

 with the object of collecting parasites in sufficient quantity 

 for shipment to Florida. Difficulties arose from the start. 

 We have seen how the white fly larva soon after emergence 

 from the egg becomes stationary upon the leaf, and if an 

 infested leaf be broken off and thereby killed, the larva dies 

 also through lack of nourishment. To use Mr Woglum's own 

 words : " Prospaltella is dependent on the living condition 

 of its host in order to attain maturity. From a considera- 

 tion of this situation, it was at once evident that the only 

 practicable way of transporting the parasite to America in 

 a living condition was by means of healthy nursery trees, 

 infested with parasitised Aleyrodes citri. Moreover, the 

 journey from India to Florida occupies between five and 

 six weeks, while the entire life-cycle of the parasite, at 

 high temperatures, is of about three weeks duration. This 

 would mean that, even if the parasite left India in the egg 

 stage, a complete cycle of development would take place 

 and the adults emerge before America was reached. This 



