As another method of describing our results, we may add that 

 our data show that, with the highest range of temperatures regis- 

 tered at Olney this season, an entire generation of the codling-moth 

 from the egg thru the larva, pupa, and adult around to the egg 

 again, might have been produced in forty days; but that under 

 the lowest temperatures which prevailed there for any considerable 

 time, eighty-two days might have been necessary for the same 

 course of development. 



Having thus clearly shown the pronounced effect of differences 

 of temperature on the rate of development of the codling-moth — 

 the effect of unusually warm weather in bringing forward the sec- 

 ond and third generations at unusually early dates and in multi- 

 plying immensely, as a consequence, the numbers of the third or 

 last generation of the apple-worms in fall — we may now turn to a 

 comparison of the Olney records of this year and last year and of 

 both these years with the records of a normal or average year, for 

 the weather of neither of the last two years was normal in southern 

 Illinois. 



The diagram on page 11 (Diagram 2) gives a carefully prepared 

 illustration of the temperature data for Olney in 1914, 1915, and a 

 normal year, the 1915 data being from our own observations and 

 the others from the reports of the U. S. Weather bureau. Follow- 

 ing across the diagram the line of equal short dashes showing the 

 monthly means for 1914, and the line of alternate long and short 

 dashes for 1915, we see that the month of April in 1915 was 

 seven degrees warmer than in the preceding year, but that May, 

 June, July, and August were from 4 to 7.5 degrees colder in 1915. 

 September was about four degrees warmer in 1915 than in 1914, 

 while in October the two lines run practically the same. Compar- 

 ing the course of the 1915 line with that of the unbroken line repre- 

 senting the weather of a normal year, we find that in April and Sep- 

 tember the temperatures of 1915 were higher than normal, but that in 

 all the rest of the season they were farther below the average than 

 those of 1914 were above it. When we call attention to the further 

 fact that the excess of heat in 1914 and the deficiency of heat in 1915 

 both came in the midsummer months, when 'insect life is at its highest 

 point and temperatures are most effective, the consequences to the life 

 history of the codling-moth will be readily understood. For the three 

 summer months the deficiency in heat this year was 50 percent greater 

 than the excess of heat last year. This year the insect was retarded in 

 its development and reduced in its numbers much below the average 

 by the same causes which last year produced an accelerated devel- 

 opment and an overwhelming production of young apple-worms 

 towards the end of the season in the second and third generations. 



So much for the Olney record; which we have given rather 

 fully because it is much the most detailed and complete. A few 



