Ll. Lloyd 



79 



days after their pupation. In August only 17 per cent, emerged in the 

 short period (17-32 days), and 83 per cent, are still pupae after 90-120 

 days. These were exposed throughout the first 60 days after their 

 pupation to a higher temperature than those which pupated in the 

 laboratory in June, though the latter all emerged in the short period. 

 None of those which pupated in September have yet produced moths. 



Table IV. Showing the behaviour of the pupae from April to November, 

 and the partial influence of temperature on the pupation period. 



o < 



Month 

 April 

 May 

 June 



July 

 August 

 September 

 - October 



Temperatures 

 Mean Range 



fMay 

 June 

 July 



•§ I August 

 ^ [_ September 



73-2° 

 70-9° 

 70-8° 

 71-3° 

 70-7° 

 63-3° 



65-0° 

 64-2° 

 64-7° 

 68-2° 

 64-5° 



58-89° 

 54-90° 

 54-90° 

 52-94° 

 52-90° 

 48-79° 



56-76° 



50-82° 

 52-77° 

 53-83° 

 44-82° 



No. of 

 pupae 



11 

 85 

 65 

 30 

 110 

 15 



20 



23 



2 



39 



No. of moths which emerged after 



Short period 





 82 (17-31 days) 

 63(20-50 „ ) 

 23 (16-35 „ ) 

 37 (17-32 „ ) 







20 (24-35 



23 (28-43 



2 (20-22 



6 (23-35 



Long period 



10 (102-200 days) 

 1 (122 days) 

 



Nos. which remain 

 pupae, or died 



1 after 200 days 

 2 died 

 2 died 

 7 after 120-150 days 

 73 „ 90-120 „ 

 15 „ 60-90 



33 after 90-120 days 



The influence of the temperature on the pupation period was in- 

 vestigated in the following experiments. Mr Bacot exposed pupae and 

 mature larvae to low temperatures in the cool and cold rooms at the 

 Lister Institute at Chelsea during August. The pupae were chilled by 

 exposure for one week to a temperature of 54° F. (50-59°), followed by 

 a week at 31-5° (28-35°); they were then kept in the laboratory for 

 three weeks, and finally returned to the greenhouse. The mature larvae 

 were exposed for a fortnight at 54° F., but not to a freezing temperature, 

 and they pupated during this time. They were then returned to the 

 laboratory and greenhouse with the other chilled pupae. Control pupae 

 and larvae had been kept continuously in the tomato house. 



One of those chilled had pupated the last week in April, and the moth 

 emerged five days after its return to the greenhouse. The pupation 

 period was 141 days, midway between the limits of the emergences of 

 the controls (102-200 days), so no effect from the chilling is apparent 

 in this case. 



Twelve pupae which had pupated at the end of July and the be- 

 ginning of August were chilled, and three moths emerged from these 



