AN APPARATUS FOR THE DETERMINATION OF OPTIMUMS 

 OF TEMPERATURE AND MOISTURE. 



By Thomas J. Headlee, 

 Manhattan, Kansas. 



Pioneer work in economic entomology consisted in the 

 determination of the insect's life history and habits without more 

 than casual regard to the environment in which it lived. From 

 time to time, however, various workers have called attention 

 to the fatal effects of the extremes of temperature and moisture, 

 and a few persons have pursued systematic inquiry into the rela- 

 tions existing between temperature and insect life. Others have 

 used various arthropods in determining the response of proto- 

 plasm to various stimuli. The last two types of investigation 

 have proceeded far enough to show that insects in common with 

 other organisms have minimum, optimum and maximum rela- 

 tions to each important stimulus to which the^^ are subjected. 

 More than enough work has been, done to show that the life 

 economy of the insect depends to a ^■ery large extent directly 

 and indirectly upon the physical, chemical, and animate environ- 

 ment in which it lives, and that no fundamental understanding 

 of its life economy can be reached until the effect of its environ- 

 ment is understood. 



While the study necessary to the accumulation of sufficient 

 data to arrive at such an understanding is one requiring much 

 time and expense, certain insects are of such transcendent eco- 

 nomic importance that the expenditure of enough time and money 

 to make the most exhaustive study is entirely justifiable. Such 

 insects have as a rule already received pioneer study and a few, 

 owing to their especially marked response to en\-ironmental fac- 

 tors, have received more fundamental attention. The writer 

 was first led to see the necessity for making a more fundamental 

 study of highly injurious species by the observation that for cer- 

 tain of the insects most injurious to staple crop production — 

 insects that exact a yearly toll of millions from the state in which 

 he is now located — only inadequate measures of control have 

 been devised, although they have been subjects of study for many 

 years. 



In making a study of the relation of environmental factors to 

 the life economy of insects, either the investigator must deal 

 with a sufTficiently large number of individuals and instances to 



147 



