78 Habits of tit e Tomato Moth 



very considerably. It is known that in nature there is often a partial 

 second flight of this moth in the autumn. This is derived from the larvae 

 which become full-fed in July and August, some of which produce moths 

 in three or four weeks in warm years, while others do not respond to 

 the favourable temperatures but remain as pupae till the following 

 summer. If the autumn proves unfavourable to the second flight and 

 none of their offspring survive to maturity, those which have not 

 emerged carry on the species the following year. Although the tempera- 

 tures in the tomato houses are fairly equable from the beginning of 

 spring to the end of autumn the same phenomenon is seen and the 

 response of the pupae to the favourable temperatures varies. 



The history of the pupae which were observed in the tomato house 

 and the laboratory is given in Table IV. Those which were kept in the 

 greenhouse were in the shade under the staging and were, for the most 

 part, on moist soil in glass jars. A thermometer was kept among them 

 and the temperatures were recorded daily. Those in the laboratory were 

 in similar jars out of the sun. The table shows the mean, absolute 

 maximum and absolute minimum temperatures for each month. It also 

 shows the number of pupae which pupated in each month ; the numbers 

 of these from which moths emerged after shorter or longer periods, with 

 the possible limits of these periods in brackets; and a note on the pupae 

 not accounted for in the previous columns. It will be seen that the pupae 

 in the laboratory behaved similarly to those in the greenhouse, in spite 

 of the fact that they were exposed to somewhat lower temperatures. 

 On the average the pupation period in the laboratory was slightly pro- 

 longed, and it was evident that there is some factor in addition to 

 temperature which partially influences the period. An account of those 

 kept continuously in the tomato house follows. 



None of those which pupated at the end of April produced moths 

 in the shorter period, but most of them emerged in a period varying 

 from 100 to 200 days. All but one of those which pupated in May 

 emerged in a short period (17-31 days). The one which delayed its 

 emergence in this month became a moth about the 122nd day. All 

 those which pupated in June became moths after a short time (20-50 

 days), but took on the average rather longer than the May pupae. This 

 was probably due to a spell of cold weather at the end of the month 

 when the temperature in the greenhouse fell to 54° F. on several occa- 

 sions. Prolonged pupation was again in evidence among the July pupae, 

 as three-quarters of them emerged in less than 35 days, and the re- 

 mainder have not produced moths up to the end of November, 120-150 



