180 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



Mr. W. C. O'Kane: In examining the curve I see that some are 

 computed from as few as three or four points. I want to ask Mr. 

 Peairs if he feels that he had absolute control over moisture and light. 

 It seems to me that where you are computing a curve and you have 

 only three or fours points, that unless you have absolute control over 

 moisture and light you may be misled. 



Mr. L. M. Peairs: The control was not absolute of course. At 

 the present time I am working with different species of flies and have 

 incubators running where I am controlling both light and moisture 

 and while I did not use any of this data in the paper presented, the 

 information which is being secured seems to bear out the conclusions 

 which have just been given. 



Mr. C Gordon Hewitt: I presume the same type of food has 

 been used throughout the experiment. The rate of development is 

 considerably influenced by the nature of the food as well as the factors 

 of temperature and moisture. The chief interest in this work lies in- 

 the fact of the use we may be able to make of extremes in temperature. 

 The sooner we get these facts, the sooner we will be able to secure value 

 from experimental data of this sort. 



Mr. V. E. Shelford: I would like to ask what precaution was 

 taken in ventilating the cages? 



Mr. L. M. Peairs: The ventilation was measured by pumps. In 

 answer to Doctor Hewitt's question I will state that most of the in- 

 sects under observation were either in the egg or pupal stages so that 

 no food was required. 



Mr. a. F. Conradi: The work in South Carolina has been directed 

 towards securing moisture control. We have an elaborate machine 

 by which we have tried to determine the moisture and the amount of 

 air passing through the rooms. Heredity also comes in, as an important 

 factor and should be given consideration as well as moisture and 

 temperature. 



Mr. C. Gordon Hewitt: We should take into consideration the 

 hereditary disposition of the different stages. 



Mr. W. C. O'Kane: If the transformations are computable on a 

 mathematical or geometrical basis, how are we going to account 

 for the delayed development of pupse under natural conditions? In 

 some places we have development occurring with some individuals 

 within a few weeks after they are laid, while other eggs under the same 

 conditions do not develop until the following summer. 



Mr. L. M. Peairs: There are certain phenomena that actually 

 occur in variance with our theories as presented. So far we have been 

 unable to explain them on any grounds other than heredity, and hered- 

 ity is a factor that we can not control in experimental work. 



