TEMPERATURE IN THE DEVELOPMENT OF ANTS. 3^3 



26, 1905, when I removed the nest to a room having a usual 

 temperature of 70 F. No more pupae developed thereafter 

 until late in the succeeding summer. The larvae remained in 

 a state of arrested development from the end of January until the 

 end of the following June, when, under the influence of the natu- 

 ral rise in summer heat, they entered upon a period of renewed 

 growth and in August presented me with ten more pupae. 



This queen laid eggs in June, when the temperature rose to 

 75 F., and continued to deposit them at various times throughout 



the summer. 



EXPERIMENT C. 



A group of thirty workers, majors and minors, of Cainponotus 

 hcrcnleaiiHS pictns hatched between July 11 and 31, 1904, were 

 kept at the temperature of 70 F. or 22 C. until November 20, 

 when they were removed to a chamber whose usual temperature 

 was from 82 to 85 F. or 28 to 30 C. On March 26, 1905, 

 they were returned to their place in my living-room, where the 

 temperature was usually at 70 F. They laid no eggs until 

 May 14, and then deposited about fifty before June 4, 1905, 

 apparently under the influence of a rise in the temperature to 

 78 F. or 25 C. 



The age of these ants may, however, have had influence on 

 the time of egg-laying. It would be interesting to ascertain, by 

 dissections of worker-ants, whether differences in the degree of 

 development of the ovaries in workers of the same species is 

 correlated with difference of age in the respective workers. It 

 may be that the ovaries of many worker-ants do not develop 

 until some months, or until the second season, after hatching. 



EXPERIMENT D. 



A group of fifty workers, Formica argcntata hatched during 

 September, 1904, were kept by me at a fairly steady temperature 

 of 70 F., and laid no eggs until after they were removed to a 

 chamber having a usual temperature of from 82 to 85 F. 

 Their first egg was deposited on January I, 1905, and during the 

 ensuing week the eggs increased rapidly in number, so that on 

 January 8 there were more than one hundred. The first larva 

 was observed on January 15. None of the larvae reached the 



