CASES USED IN TEANSPORTING PAEASITES. 35 



was of such height that the top of the young trees placed thereon 

 would approximate or slightly exceed the height of the hedge. (See 

 PI. VIII, figs. 2, 3.) 



Potted plants were arranged on this platform immediately preced- 

 ing the emergence of the brood of the white fly in September. The 

 awning was then so extended as completely to cover the hedge except 

 at the side on which the plants were placed. This procedure not only 

 protected the foUage from the sun but so shaded the hedge that when 

 the white flies became active in the morning and evening they would 

 come in contact with the potted trees, in their flight toward the light, 

 and thus be more likely to oviposit thereon than upon the hedge itself. 

 AU fresh and tender foliage was removed from the hedge before 

 emergence of the white fly took place so as to render its fohage less 

 attractive than that of the potted plants. As a result the flies ovi- 

 posited freely on the young plants and a gross infestation was thereby 

 secured. 



The plants w"ere continued in this position after infestation in order 

 to afford natural conditions for the action of parasites. About the time 

 white-fly eggs commenced to hatch, parasites could be seen running 

 about the young plants, and later it was found that the percentage 

 of parasitism on the 3^oung trees was equally as great as had been 

 seen on the infested hedge at any period during the observations. 



It was now the middle of October and, believing that all conditions 

 at that time were most opportune for success in carrying through the 

 parasite to America in good condition, the writer commenced boxing 

 the plants on October 18 preparatory to shipment. 



Cases Used in Transporting Parasites. 



When tender plants are shipped long distances, as from one country 

 to another, a specially made crate called a Wardian case has been 

 used with marked success. These cases much resemble miniature 

 greenhouses, being constructed of heavy wood throughout with the 

 exception of the top, which is made of glass. The cases are perfectly 

 tight except for two small holes at the top, which afford a slight ex- 

 change of ail' with the outside. Plants contained in these cases go 

 great distances without watering. The A\Titer's attention was called 

 to this case by JVIr. C. L. j\Iarlatt, assistant chief of this bureau, and 

 by ]Mr. David Fairchild, in charge of plant introductions in the Bureau 

 of Plant Industry of this department. Request for one of these cases 

 was made to the Government Botanical Garden, Calcutta, and in due 

 time a sample case was constructed and shipped to Lahore. These 

 Wardian cases are used for seedling plants, and consequently are low- 

 topped. It was found that in order to utilize this type of case for our 

 insect-infested plants it would be necessary to make a number of altera- 

 tions. This was done and the completed case as used f(^ transporting 



