Ll. Lloyd 81 



hibernation, but fails to abolish it in all within the limits tested. An 

 artificial cooling may intensify it, or even make it total. The susceptible 

 period in the insect's life is in the late larval and early pupal condition. 

 At the commencement of this work, judging by what was known at 

 that time, it appeared that it might be possible to force all to emerge 

 from the pupae by keeping up the temperatures of the greenhouses at 

 the end of the growing season when there is no food for the larvae in 

 the houses, and that the moths could then be destroyed by fumigating. 

 The foregoing facts show that this is impracticable as the pupae would 

 resist forcing at any temperatures to which the tomato houses could 

 be raised. . 



[The following note completes the history of the pupae kept under 

 observation through the winter in a greenhouse continuously heated. 

 No moths emerged from September 5 to December 10, and very few in 

 the latter month and in January. There was little relation between the 

 dates of pupation and the dates of emergence of the moths. The longest 

 pupation period was about 300 days (August to May). Those which had 

 not emerged by the end of May were found to be dead. 



3. THE INFESTATION. 



In captivity the shortest entire life cycle from moth to moth, when 

 the larva was fed on tomato foliage, was 55 days. The eggs were laid 

 on July 4; hatched on July 11 (7 days); larva matured and burrowed 

 on August 6 (27 days); pupated August 8 (2 days); moth emerged 

 August 27 (19 days). The mean temperature during this time was 

 72° F. (Range 52-94°). The life cycle under natural conditions in the 

 tomato houses occupied rather longer on the average. 



The life history of the insect was studied by the systematic examina- 

 tion of the 1600 plants in a 200-foot house from the end of April to the 

 middle of September. This house was heated up in January and used 

 for propagating one lot of plants in the early part of the year. It was 

 planted out the second week in April. For the purposes of this experi- 

 ment it was isolated from the rest of the block by a stretch of hessian 



Ann. Biol, vn 6 



