Ll. Lloyd 



77 



starvation. The conclusion drawn was that the moth could pass through 

 its life history in a cucumber house if weeds were allowed to grow there, 

 since in all its stages it can survive the high temperature and humidity. 

 Table III shows the effect of the various food plants employed on 

 the duration of the active life of the larvae, only those which were 

 confined to one diet, and which formed healthy pupae, being included. 

 It shows also that the higher temperatures of the tomato houses increase 

 the rapidity of the development on each food. The average life of the 

 larvae in the houses under natural conditions, estimated by regular 

 counts of them at different stages, appears to be between 35 and 45 days. 



Table III. Showing the effects of various foods and temperatures 

 on the duration of the larval life. 



When full-fed the larvae seek out moderately dry places in which 

 to pupate. Experience in the nurseries shows that they will travel 

 considerable distances in search of suitable sites, and will spin up in 

 crevices in the walls and woodwork, and in sacking, or sometimes among 

 the leaves of the plants. On a heavy wet clay soil most of them pupate 

 in the structure of the glasshouse, but where the soil is light and friable 

 the majority pupate there, especially under the pipes or round the 

 concrete piers. The pupae are frequently found in the mulch, or just 

 below it, and very rarely indeed at a greater depth in the ground than 

 one inch. They are often seen in the unfaced joints of the pipes, and in 

 the tops of the canes used for plant staking. In such places the larvae 

 spin light silken cocoons and remain quiescent for two or three days 

 before pupating. The pupa is smooth, shining, and normally almost 

 black, though occasionally lighter specimens are seen. 



The period during which the insect remains in the pupal stage varies 



