THE DOCK FALSE-WORM. 



19 



Opposition of spring-brood adults. — Spring-brood adults begin ovi- 

 positing within a day of emergence. The maximum period observed 

 was 9 days, with an average of 2.9 days, figuring from date of emer- 

 gence to date of deposition of each egg. Six mated females of the 

 spring brood deposited an average of 103.6 eggs, the maximum being 

 117 and the minimum 89; five single females deposited an average 

 of 109.4 eggs, with a maximum of 125 and a minimum of 102. 



FIRST GENERATION. 



Incubation period of first-brood eggs. — Table V gives the length of 

 the egg stage for 446 fertile eggs and 301 parthenogenetic eggs de- 

 posited by spring-brood females in living plants. The fertile eggs of 

 this brood have an average incubation period of 10.7 days, as against 

 9.9 days for the parthenogenetic eggs. 



Table V. — Length of the incubation period of first-brood eggs of the dock false-worm, 



Wenatchee, Wash., 1915. 



Fertile eggs. 



Num- 

 ber of 

 eggs. 



a 



7 



43 



102 



6 



25 



i 



2" 

 1 

 12 



50 



9 



1 

 1 



Date- 



Deposited. Hatched 



Apr. 25-26 



do 



Apr. 25-27 



do 



do ..... 



Apr. 28-29 



do 



do 



Apr. 29 



do 



do 



do 



Apr.30-May-5. 



do 



....do 



do 



....do 



May 

 May 

 May 

 May 

 May 

 May 

 May 

 Ma v 

 May 

 May 

 May 

 May 

 May 

 May 



May 

 May 



Incu- 

 bation 

 pe- 

 riod. 



11.5 



12.5 



11 



12 



13 

 9.5 



10.5 



11.5 



10 



11 



12 



14 

 8.5 

 9.5 



10.5 



! 2. 5 



11 



12 



Total 

 days. 



332 



62.5 

 1,078 

 528 



91 



40S. 5 

 1,071 



69 

 250 



44 



24 



14 

 102 



76 

 525 

 112.5 



11 



12 



146 



period . 



Maximum 



Minimum 



I 800.5 



10.7 

 11 



6 



Parthenogenetic eggs. 



Num- 

 ber of 

 eggs. 



Date — 



Deposited. Hatched 



Apr. 29 



do 



do 



do 



do 



Apr. 29-May 5 



do 



May 5-9 



do 



do 



do 



do 



May 5-8 



do 



do 



do 



do 



....do 



May 9 



do 



....do 



May 25 



May 26 



....do 



May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 Mav 

 ...do. 

 May 

 M ay 

 .lime 

 June 

 June 



Incu- 

 bation 

 pe- 

 riod. 



10 



11 



12 

 7.5 

 8.5 

 9.5 



10.5 



11.5 



12.5 



10 



12 



15 

 9 

 9 



10 



Total 

 days. 



■ Incub "' Ion period . 



Maximum 



Minimum 



860 

 110 



12 



13 



16 



132 



10S 



12S 



9 



60 



55 



24 



90 

 263. 5 



76 

 220.5 

 1S4 

 100 



40 



36 



30 

 342 



45 



30 



2,984 

 9.9 



in 

 6 



Length <rj life of first-brood larva by instars. Seventy larvse from. 

 fertile egg* were reared, at least to the third instar, but of these only 

 31 were carried to the pupa] stage. A partial record was obtained of 

 l!) parthenogenetic larvae, and a complete record of 8. Table VI 

 give-, a summary of the length <>!' larval life by instars, of all larvae 

 reared. 



