PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 61. 



same period of time, perishing two days after oviposition was com- 

 plete. 



On the morning of April 3, 1921, two unfertilized females were 

 taken in the field and after being permitted to mate were placed in 

 cages in the laboratory where daily count of the eggs deposited by 

 each beetle was made and the eggs removed at about 5 o'clock in the 

 afternoon. The results were as follows: 



No. 



1 had deposited — 



April 4 



April 5 



April (5 



April 7 



April 8 



April 9 



April 10 



April 11 



April 12 



April 13 



Eggs. 



. 1,01'! 



392 



165 



118 



87 



60 



27 



28 



26 



1 



April 17, the beetle died. 



No. 



2 had 



April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 

 April 



deposited — 



4 



5 



6 



7 



9_ 

 10- 

 11_ 

 12_ 

 13_ 

 14_ 

 15- 

 16- 

 17- 

 18- 

 19- 



Eggs. 

 . 374 

 . 487 

 . 249 

 . 213 

 . 107 

 . 79 



- 41 

 . 77 



- 81 



- 27 



- 14 

 . 25 

 . 5 



- 4 

 . 1 

 . 3 



April 21, the beetle died. 



In the case of No. 1. the beetle deposited a total of 1,925 eggs 

 within a period of 10 days, perishing 4 days after oviposition was 

 complete. In the case of No. 2, a total of 1,786 eggs was deposited 

 within a period of 16 days, the beetle perishing 2 days after oviposi- 

 tion was complete. It will be well, however, to note that these re- 

 sults were obtained under laboratory conditions where the environ- 

 ment was very favorable and practically unchanged; consequently, 

 they do not show accurately what transpires in the fields where hot 

 days and cold nights, violent rains and drying winds play a very 

 important part in determining the length of the period of ovipo- 

 sition and the power of the female to deposit the maximum number 

 of eggs . 



The period of incubation of the egg is variable, depending upon 

 temperature as the main determining factor. Under laboratory con- 

 ditions where the temperature varied but slightly above or below 

 70° F., the time required for the eggs to hatch was from twelve to 

 fourteen days. In the field, where temperature conditions are ex- 

 ceedingly variable at the iime the eggs are present, the period of 

 incubation is considerably longer than that required in the labora- 

 tory. Out of repeated attempts to carry eggs in the field through 

 the period of incubation only one proved successful. The eggs used 

 were deposited in the laboratory on March 30 and 31, 1921, and 



