PLATE 10 



Fig. 4. Histograms showing abundance of aggregate forms, or number 

 obtained per hour from the surface relative to temperatures between 15?9C and 

 18?3C (left), and 18?4C and 20?8C (right); (a) based on all data pertaining to 

 June and July, 1908 and 1909 (table 4); (b) based on night data (table 5); (c) 

 based on day data (table 6A) ; (d) based on intense light data (table 6B) ; (e) 

 based on early morning data (table 6C); (f) based on evening data (table 6D) ; 

 (g) based on June, 1909 data (table 8); (h) based on data restricted to collec- 

 tions made within one mile of each other (table 10). 



Fig. 5. Histograms showing ahundance of solitary forms relative to the same 

 conditions as specified in the explanation of figure 4. 



Fig. 6. Histograms showing abundance of aggregate forms on the surface 

 relative to temperatures between 15?9C (left) and 20?8C (right), divided into (a) 

 three groups each having a range of 1?6C (table 11) ; (&) four groups each having 

 a range of 1?2C or 1?3C (table 12) ; (c) five groups each having a range of one 

 degree (table 13); and (d) six groups each having a range of 0?8C (table 14). 



Fig. 7. Histograms showing abundance of solitary forms relative to the same 

 conditions as specified in the explanation of figure 6. 



[296] 



