30 



BULLETIN 491, U. S. DEPARTMENT OF AGRICULTURE. 



ited. Females will deposit eggs on the sides of the containing recep- 

 tacles if they are not given fruit in which to oviposit. They do not 

 seem, however, to deposit as freely as when placed with fruits. A 

 small number of flies, still alive of those emerging from pupae in 

 February 17, 1914, were observed to lay, as usual, a few eggs on the 

 sides of the containing jars. A record of the eggs deposited was 

 made every few days, beginning with December 17, 1914, and ending 

 April 4, when the last female died. The record of these eggs appears 

 in Table I under the subject of longevhVy of adults. The dates on 

 which the observations were made were arbitrarily chosen to conform 

 with other laboratory work and are not necessarily those on which 

 the eggs were actually laid. When one considers that these females 

 had no fruit offered them throughout their life, the number of eggs 

 laid is very interesting; thus 11 eggs were deposited between March 

 22 and 25, or from 398 to 400 days after the flies emerged. 



Ability to resume normal oviposition after period of scarcity of 

 host fruits. — The data in Tables III and IV are valuable, inasmuch 

 as they demonstrate that the female melon fly which has been de- 

 prived of all opportunity to oviposit in fruit can begin ovipositing at 

 the normal rate when host fruits become available. Thus the three 

 flies whose records are included in Table III had been kept in glass 

 jars from the date of their emergence from pupae on February 17 

 until May 22, or about 13 weeks, while the two whose records appear 

 in Table IV were not given an opportunity to oviposit in fruits until 

 October 8 and November 26, respectively, or from about 31 weeks to 

 about 37 weeks after emergence. 



Table III. — Daily rate of oviposition of melon flies that emerged on February 

 11 and were placed separately with fruit on May 22, 1914. 



Date. 1 



Number of eggs deposited. 



Date. 



Number of eggs deposited. 



Fly No. 1. 



Fly No. 2. 



Fly No. 3. 



Fly No. 1. 



Fly No. 2. 



Fly No. 3. 



May 22 



21 



14 

 4 







Aug. 3. 



13 







30 



2 





4 





12 

 17 



31 



2 



8 





8 





17 

 13 



9 .. 



8 



10 

 10 





8 







10 





21 



15 





9 



12 . 





21 



16 



1 





15 





22 



17 



12 





16... 





12 





21 



10 



17 



12 





23 



4 



io~ 



18 





14 



28 





19 



9 

 16 

 2 







30 



18 





22 







7 



, 



25 . 





13 



3 



29 



17 



15 



16 







1 



30 



7 







16 



3 

 16 

 2 



Sept. 3 





( 2 ) 



19 







6 . 



( 2 ) 





21 









17 



12 



29 

 ( 3 ) 





24 



14 



i7~i 



13 I 



4 



23 







26 





24 . 









8 



28 



Total 









30 



31 



200 



191 | 162 



1 Dates on which none of the flies oviposited are omitted from the table. 



2 Died on this date; no eggs in abdomen. 



s Adult lost. 



