28 



BULLETIN 265, U. S. DEPARTMENT OF AGRICULTURE. 



One mated female deposited a total of 133 eggs, and another escaped 

 after depositing 95 eggs. Two single females were observed one 

 of which deposited 83 eggs and the other 104. 



FOURTH GENERATION. 



Incubation -period of fourth-brood eggs. — The length of the fourth- 

 brood egg stage averages a little shorter than that of the second 

 brood, the weather in August being warmer than in June. Records 

 of 174 fertile eggs showed an average incubation period of 3.8 days, 

 and records of 62 parthenogenetic eggs deposited during the same 

 period showed an average of 4.4 days. Table XVIII gives the 

 records for the 174 fertile eggs, and for 157 parthenogenetic eggs, 

 95 of them being deposited from August 31 to September 4, when the 

 weather was cooler. This makes the total average higher than that 

 of the fertile eggs, as no records of these were secured during this 

 cooler period. 



Table XVIII. — Length of the incubation period of fourth-brood eggs of the dock false- 

 worm, Wenatchee, Wash., 1915. 



Fertile - 



Number 

 of eggs. 



Date- 



De- 

 posited. 



Hatched. 



Aug. 



18 



...do. 





...do. 





Aug. 



19 



...do. 





...do. 





...do. 





Aug. 



20 



...do. 





...do. 





Aug. 



21 



...do. 





...do. 





Aug. 21 

 Aug. 22 

 Aug. 23 

 Aug. 22 

 Aug. 23 

 Aug. 24 

 Aug. 25 

 Aug. 24 

 Aug. 25 

 Aug. 26 

 Aug. 24 

 Aug. 25 

 Aug. 26 



Incu- 

 bation 

 period. 



Total 

 days. 



3 

 104 

 95 

 123 

 112 

 30 

 6 

 100 

 5 



6 

 33 



44 

 15 



676 



Average incubation period . 



Maximum 



Minimum 



3.8 



Parthenogenetic eggs. 



Number 

 of eggs. 



Date- 



De- 

 posited. 



Aug. 

 ...do. 

 Aug. 

 ...do. 

 Aug. 

 ...do. 

 Aug. 

 Aug. 

 ...do. 

 ...do. 

 ...do. 

 Sept. 

 ...do. 

 ...do. 

 Sept. 

 Sept. 

 ...do. 

 ...do. 

 Sept. 



Hatched. 



Aug. 24 

 Aug. 25 



..do 



Aug. 26 



..do 



Aug. 27 



..do 



Sept. 6 

 Sept. 7 

 Sept. 8 

 Sept. 9 

 Sept. 7 

 Sept. 8 

 Sept. 9 



2 j Sept. 8 



3 L.do 



..; Sept. 9 

 . . I Sept. 10 



4 | Sept. 11 



Incu- 

 bation 

 period. 



Average incubation period . 



Maximum 



Minimum 



Total 

 days. 



56 

 60 

 40 

 55 

 32 

 30 



4 



6 

 126 

 16 

 18 

 60 

 133 



8 

 84 



5 

 120 

 21 



902 



o. I 



9 

 4 



Length oj life of fourth-brood larvae by instars. — As the fourth-brood 

 larvae do not pupate the same season, but pass the winter in the 

 larval stage, only the period from hatching to the forming of the pupal 

 or hibernating cell by these larvae is given in the summary in 

 Table XIX.- 



