MONTHLY BULLETIN. 



305 



Common potatoes were spread on the lioor of the greenhouse, under 

 the benches, on April 1st. On April 9th they commenced to sprout. 

 They were then placed in box trays 3 inches deep and of a standard 

 size so as to fit the cages in which they were to be used. The cages hold 

 four trays, one above the other when filled, and are operated as follows : 

 One tray of infested potato sprouts is placed in the cage, together with 

 the ladybirds or parasites. "When the supply of mealy bugs in this tray 

 is exhausted it will of course contain a large "number of immature forms 

 of ladybirds or parasites as the case may be. This tray is then shifted 

 to the bottom of the cage and a fresh tray filled with mealy bug-infested 

 potato sprouts placed immediately above it. This gives an opportunity 

 for the ladybird larvae to crawl up where there is plenty of food avail- 

 able. This procedure is continued until all four trays are in the cage. 



The bottom of the tray is filled with sand about one inch deep and 

 the potatoes fitted in closely and moistened. The trays are then 

 placed in a large cupboard-like cage, holding about 20 trays. This 

 cage is darkened by means of a heavy canvas curtain and kept in a 





Fig. 99. — Showing potato sprouts heavily infested with mealy bugs. (Original.) 



warm greenhouse. (See Fig. 98.) The sprouts grow very rapidly and 

 are stocked by placing in each tray a number of lemons or potato 

 sprouts infested with young mealy bugs. In this particular instance the 

 sprouts Avere 10 to 12 inches long by May 14, and very heavily infested 

 with young mealy bugs. (See Fig. 99.) The infested sprouts may be 

 cut off if desired for feed, since they will keep fresh for 10 or 12 days 



