174 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



year with lime-sulphur wash and the third was sprayed the same year 

 with soluble oil on the lower branches. The lower branches of all 

 three showed practically the same effect, as near as I can judge, as 

 those mentioned by Doctor Felt. It was, however, a very unusual 

 condition. I would like to ask Doctor Felt if he has found this con- 

 dition in trees that have not been sprayed with miscible oil. 



Mr. E. p. Felt: We have observed trees in apparently the same 

 condition, though in our own experience a close examination has shown 

 differences from the symptoms which we have noted as following the 

 application of miscible oils. 



Mr. W. M. Scott: As I understand it this injury was confined to 

 sugar maples; other maples were not affected by this spraying? 



Mr. E. p. Felt: My observations in this particular case related to 

 the sugar maple and the ordinary soft or white maple. The latter 

 seem to be fairly tolerant, the sugar maple quite susceptible to injury. 



President P. J. Parrott: The next paper will be presented by 

 Mr. L, M. Peairs, entitled, "The Relation of Temperature to Insect 

 Development. " 



THE RELATION OF TEMPERATURE TO INSECT 

 DEVELOPMENT 



By L. M. Peairs, Morgantown, W. Va. 



At meetings of the American Association of Economic Entomol- 

 ogists held in Chicago in 1907-1908 and in Boston in 1909, Director 

 E. D. Sanderson, then of the New Hampshire Experiment Station, 

 presented papers dealing with the relation of heat to the various 

 activities of insects, notably with the effect of heat on development, 

 distribution and hibernation of insects.^ The papers were based on 

 an accumulation of data taken by him at the New Hampshire Station 

 and included some results from other sources. The last paper had 

 also a resume of the existing theories of the effect of heat upon develop- 

 ment and showed some of the weaknesses of those theories, at the same 

 time advancing theories of his own on the subject. These theories, 

 as worked out by the writer from the data of Director Sanderson with 

 additions from other sources, have proved to be remarkably sound. 

 The theory offered for the proper method of computing accumulated 

 temperatures (Jour. Ec. Ent., Vol. Ill, pp. 136-137) is shown in the 

 present paper to be correct. Fig. 10-15 and the accompanying discus- 

 sion well illustrates this point. 



1 Journal of Economic Entomologj', Vol. I, pp. 56-65, 245-262, and Vol. Ill, pp. 

 113-140. 



