250 
Graph 7 combines Graphs 5 and 6, and also shows the curve of 
development. The circles show the position of the points when the 
reciprocals of the periods (Table 7, column 4) are plotted against the 
average mean daily temperature (column 5) ; the dots show the position 
of the points when the reciprocals of the periods are plotted against 
the average day-degrees above 52° (column 7); the dots with crosses 
show the position of the same points when the average daily effective 
rres sSaand Sears gessaest 
Ht 
+ 
a 
T 
rs 
rf 
+ 
Blsnefases jeseees f 
t + 
nr a a a a a, ae a |e MT ay aL aa TT) 
Grapu 6. Pupal period. Reciprocals of the periods plotted 
against average daily effective day-degrees. 
day-degrees after corrections were made for retarding temperatures 
above 87° (column 10) are substituted for the average mean daily tem- 
peratures in the temperature axis; and the concentric circles show the 
position of the same points when the periods in days are plotted against 
the average daily effective day-degrees. 
The latter gives an hyperbola of which the equation is EP=241, in 
which E—average daily effective day-degrees and P=period in days. 
