436 



EFPECT OF TEMPERATURE UPON FACET NUMBER 



u. 



L. 



123456789 

 DQ.L|5 at 27° 



Fig. 11. Effect on the distribution of facet counts as a result of subjecting 

 successive cultures from the same parentage of Ultra-bar to varying periods of 

 time at 27° before subsequent development at 15°. After mating the first bottle 

 was put at 27° for 24 hours. The parents were then removed to the second 

 bottle. The first bottle was allowed to complete development at 15°. At the 

 end of 24 hours, the parents were removed to a third bottle, etc. The second 

 bottle remained at 27° for 48 hours, and completed development at 15°. The 

 third bottle remained at 27° for the first 3 days, etc. The first vertical line 

 of a pair represents the range of the female counts, the second is that of the males. 

 Those cultures to the left of the first full vertical line were in the larval stage 

 when the transfer from 27 to 15° was made. Those between the two full ver- 

 tical lines were in the pupal stage when the transfer was made (see Table XV). 

 U. is the upper range of 27° stock counts; L., the lower range of 15° stock counts. 



