20 



BULLETIN 491, U. S. DEPARTMENT OE AGRICULTURE. 



larly cared for, and upon which like data were secured, died at prac- 

 tically the same rate as the flies recorded in Table I. 



Of any lot of adults kept in confinement for experimental purposes 

 fully 30 per cent may be expected to die within the first 2 to 4 weeks 

 of life, even when given the best of care and kept in jars not over- 

 crowded. Two adults emerging on August 28, 1913, died on October 

 29 and November 2, respectively. Of 15 flies issuing August 26, 1913, 

 one lived until November 27, but the others were dead by October 20. 

 Other data might be included, but they would bring out no facts to 

 disprove that the length of adult life is variable under like condi- 

 tions. The chief interest centers about the fact that certain adults 

 may live long periods and thus keep the pest alive during seasons 

 when host fruits are not in condition for oviposition. 



Table I. — Longevity of adult melon flies emerging on Feb. 17, 19 /.J. 1 



Date of observation. 



Number of 

 flies alive. 



Number of 

 flies dead. 



Date of observation. 



Number of 

 flies alive. 



Number of 

 flies dead. 



Number 



of egg s 



deposited 



on sides 



of jar. 2 



Male. 



Fe- 

 male. 



Male. 



Fe- 

 male. 



MaIe -maTe. 



Male. 



Fe- 

 male. 





21 



21 

 20 

 20 

 20 

 19 

 19 

 19 

 18 

 18 

 18 

 18 

 17 

 17 

 16 

 16 

 16 

 14 

 13 

 13 

 13 

 12 

 9 

 8 

 8 

 8 



23 

 23 

 23 

 23 







Dec. 

 Jan. 



Feb. 

 Mar. 

 Apr. 



17 



8 14 

 8 | 14 

 4 11 

 4 10 

 4 10 

 4 10 

 i in 





1 



12 



27 







22 



54 



29 . 



1 





26 



4 



3 

 1 



56 



July 7 



29 



2 



35 



10 



22 





1 



21 



13 . 



22 1 



5 







14 



16 .. 



22 

 22 

 22 

 22 

 21 

 21 

 20 

 20 

 20 





8 







6 









12 



4 

 4 

 4 



4 

 4 



3 

 2 



1 

 1 

 1 

 1 

 1 

 



10 



9 

 9 



9 







26 



3 



1 





15 



20 



25 





1 



20 



6 



58 



8 





1 







62 



19 



29 





 9 







17 



22 



1 



1 



1 



1 



1 

 1 



1 



36 



24 



4 



8 ' 



7. 1 

 7 1 

 6 



14 



27 



1 







10 





29 



20 

 19 

 17 

 17 

 17 

 16 

 16 

 16 

 16 

 15 

 15 





23 



25 



27 



5 



33 



Sept. 12 



2 

 1 



1 



2 ! 







11 



14 



fi 





37 



Oct. 16 





1 

 2 



1 

 1 





21 



11 



3 



3 1 



2 

 1 





27 



1 

 3 

 1 



1 



I 



1 



22 



11 



Nov. 7 . 



25 



11 



11 



29 







17 



31 





1 

 1 

 







25 













Dec. 2 . . 







4 







1 











I ! 









1 Mortality records were not started until June 17, or not until the flics were 4 months old. 



2 No record of eggs deposited on sides of containing jars were started until December 17, or not until 

 the flies were 10 months old. Compare data with data on daily rate of oviposition. 



Without food. — Adult melon flies die rapidly within a few days if 

 not given an opportunity to feed. This is shown by the records of 

 mortality of flies placed in clean glass jars and given no food or water, 

 but kept otherwise under conditions identical to those under which 

 flies regularly fed are kept. No flies in the following experiments 

 lived for more than 100 to 102 hours without food and water, or for 



