THE DOCK FALSE-WORM. 



29 



Table XIX. — Summary of larval life of fourth generation of the dock false-worm, from 

 hatching to forming of pupal cell, Wenatchee, Wash., 1915. 



First instar. 



Second instar. 



Third instar. 



Fourth instar. 



Fifth instar. 



Sixth instar. 





VH 





„_ . 



,_, 





<M , 



. 





•M 



OH 





._ 



«M 





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„_ 





O co 

 73 



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o K3 

 73 





OT 

 >> 



o CO 



73 



°,d 



£> 



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CO 



>> 



O o 



73 



°J3 



K) 



O vi 



73 



°A 



>> 



t- P 



u ^ 



03 



S-i 3 



c3 



i- 3 





03 



S-i 3 



fe 03 



03 



in 3 



fe 03 



03 





*-< % 



03 



KS 



g.« 



■a 



£.*2 



*3 



T3 



23 



^ 



-3 



£.-2 



"3 



T3 



£2 



^S 



-d 



ss 



£® 



-d 



n^ 



fl& 



73 



Si: 



a^ 



03 



S£ 



a* 



73 



s,£ 



n& 



C3 



s.£ 



l& 



73 



FJ£ 



flft 



73 



s* 



3 03 





rJ-C) 



S 03 





rJ-CJ 



3 ^ 





pTS 



S <3 





3x3 



3 c3 





3^ 



S 03 



■g 



fc.s 



1 



£ ,(J 



&H 



fc.H 



{25-0 



EH 



fc.9 



£ ,(J 



EH 



£.H 



J2-.U 



e 



fcjtf 



£' U 



EH 



£.3 



j25-d 



EH 



1 



1 



21 



2 



42 



1 



1 



1 



3 



2 



6 



2 



6 



12 



9 



1 



9 



7 



2 



14 



3 



3 



9 



9 



2 



18 



1 



2.5 



2.5 



2 



7 



14 



2 



2 



4 



13 



3 



39 



2 



3.5 



7 



8 



3 



24 



6 



3 



18 



4 



9 



36 



2 



4 



8 



4 

 4 



4 

 5 



16 

 20 



4 

 1 



4 



4.5 



16 



4.5 



5 



1 



4 

 6 



20 

 6 



4 

 4 



4 

 5 



16 

 20 



1 

 2 



10.5 

 11 



10.5 

 22 









13 





21 



4 



6 



24 



1 



10 



10 



1 



7 



7 



1 



6 



6 



1 



12 



12 



Av 1.6 



3 



8 



24 















1 



8 

 10 



8 

 10 



1 

 1 



1 



13 

 14 



17 



13 

 14 



17 



Max 4 



Min 1 



32 

 Ay. 





88.5 

 . 2.7 







76 

 .. 3 



36 





138 





Av 











Av 



3.8 



Max 





.. 10 



Max 



.. 7 



21 





86.5 

















Max 



8 



Min 





.. 2 



Min 



1 



Av 





. 4.1 



15 





150.5 





Min 



1 













Max 

 Min 





. 10 

 . 2 



Av. 

 Max 

 Min 





.. 10 

 .. 17 

 .. 6 





The foregoing table includes individuals from both fertile and par- 

 thenogenetic eggs, since there was but little difference between them. 



Life cycle of fourth generation. — Table XX gives a partial life cycle 

 of 13 individuals of the fourth generation, including the period from 

 oviposition to the forming of the pupal cell by the full-grown larvae. 

 This averages 32.6 days for parthenogenetic individuals and 32.7 

 days for normal individuals. In order to arrive at the complete 

 length of the life cycle of individuals of this generation, we must add 

 to this approximately 200 days, which is the average time spent by the 

 larvse in the pupal cell, and also 10.5 days, which is the average 

 length of the spring brood (fourth generation) pupal period as shown 

 in Table II. This makes an average total of about 243 days, the com- 

 plete life cycle of the fourth generation. 



Table XX. — Length of partial life cycle of the fourth generation of the dock false-worm, 



Wenatchee, Wash., 1915. 



Parthenogenetic individuals. 



Indi- 

 vidual 

 No. 



Date of— 



Days in— 



Aver- 

 age par- 

 tial life 

 cycle in 



days. 



Egg dep- 

 osition. 



Hatching. 



Forming 

 pupal 

 cell. 



Egg 

 stage. 



Larval 



stage. 



1 

 2 

 3 

 4 

 5 

 6 



Aug. 20 

 ...do 



Sept. 1 

 ...do 



Sept. 2 



Sept. 3 



Aug. 24 

 ...do 



Sept. 7 

 ...do 



Sept. 9 



Sept. 11 



Sept. 15 

 Sept. 16 

 Oct. 3 

 Oct. 6 

 Oct. 10 

 Oct. 11 



4 

 4 

 6 

 6 



7 

 8 



22 

 23 

 26 

 29 

 31 

 30 



26 

 27 

 32 

 35 

 38 

 38 



To1 



,al ,. 







35 



5.8 



m, 26 da 



' 161 



26.8 



ys. 



196 

 32. 6 



Av 

 Maxin 



erage number of days 



lum life cycle, 38 days; minimu 



