576 



Journal of Agricultural Research 



Vol. XIII, No. II 



The period from beginning of oviposition to death, to which reference 

 is made on page 575 under " Length of adult life," is the average of the 

 23 collected individuals. To give an average for the period, an insuffi- 

 cient number of specimens were reared and kept under observation 

 after being mated. 



REPRODUCTIVE HABITS 



Newly matured females have never been observed to mate in less than 

 three days. Eggs are not secured until one day later. Subsequent 

 mating is frequent and promiscuous, though a female often rejects a 

 male. 



A study was made of the reproductive activities for one day, of the 

 rate of oviposition at various hours of the day, and of the seasonal varia- 

 tion in oviposition. 



Five pairs of Nysius ericae vfere collected and each pair was confined 

 in a cotton-stoppered vial. They were watched continuously for eight 

 hours, remaining in the vials during the succeeding night. Table V 

 is a typical record. Observations began at 7.45 a. m.^ 



Tabi^E V. — Twenty-four-hour record of the reproductive activities of Nysius ericae, pair j 



Paired 9.43. 

 Parted 9.46. 

 Paired 10.21. 

 Parted 10.25. 

 Paired 10. 56^. 

 Parted 11. 01. 



Oviposited 11.22 to 11.24^ 

 (8 eggs). 



Paired 11.57. 

 Parted ii.59>^. 

 Oviposited 12.45 to 12.59 



(4 eggs). 

 Paired 1.02. 

 Parted 1.07. 

 Paired 1.09^^. 

 Parted i.io. 



Paired 1.15. 

 Parted i.i7K- 

 Paired 1.27. 

 Parted 1.29. 

 Paired 1.33. 

 Parted 1.35. 

 Paired 3.35. 

 Parted 3.37. 



"When examined the next morning at 7.45, both insects were living, 

 but no more eggs had been deposited. 



To ascertain the rate of oviposition at various hours of the day, several 

 pairs were confined and the eggs removed daily at 8 a. m., i p. m., and 

 5 p. m. The experiment continued from June 6 to August 5, the pairs 

 being replaced as they died, and by the latter date a total of 463 eggs had 

 been secured. Of this number 239 were secured at 8 a. m., 145 at i 

 p. m., and 79 at 5 p. m., or in about the ratio of 3 :2 : i. As nearly 

 as can be determined, feeding and reproductive activity cease during 

 darkness. This indicates that as many eggs are deposited during the 

 late evening and early morning as are deposited from 8 a. m. to 5 p. m., 

 and that twice as many eggs are deposited from 8 a. m. to i p. m. as 

 from I p. m. to 5 p. m. 



This decrease in reproductive activity during the afternoon has been 

 observed under field conditions, the insects feeding less and seeking shade 

 through the hot part of the afternoon. 



1 References to clock time refer to standard time. 



