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. 



28 



5 



98 



44 



43 



K)2 



6 



25 

 4 

 2 

 1 



12 

 8 



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- 



do 



....do 



do 



May 5 



....'.do 



May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 11 

 May 13 

 May 11 

 May 12 

 May 13 

 May 15 

 Mav 16 

 May 17 



10 



!(l 



Incu- 

 bation 



P e : 



nod. 



446 

 Average incubation period. 



Maximum 



Minimum 



11.5 



12.5 



11 



12 



13 

 9.5 



10.5 



11.5 



10 



11 



12 



14 

 8.5 

 9.5 



10.5 



12.5 



11 



12 



Total 

 days. 



332 



62.5 

 1,078 

 528 



91 



408. 5 

 1,071 



69 

 250 



44 



24 



14 

 102 



76 

 525 

 112.5 



11 



12 



4, 800. 5 

 10.7 

 14 



Parthenogenetic eggs. 



Num- 

 ber of 



eggs. 



301 



Date- 



Deposited. Hatched 



Apr. 29. 



do 



....do 



....do 



....do 



Apr. 29-May 5 . 



do 



May 5-9 



....do 



....do 



do 



....do 



Mav 5-8 



.....do 



....do 



do 



.....do 



....do 



May 9. 



.....do 



do 



Mav 25 



Mav 26 



.....do 



May 9 

 May 10 

 May 11 

 May 12 

 May 15 

 May 13 

 May 14 

 May 15 

 May 16 

 May 

 May 

 May 

 May 

 May 

 May 

 May 

 May 18 

 May 19 

 ..do.... 



May 21 

 May 24 

 June 3 

 June 4 

 June 5 



Incu- 

 bation 

 pe- 

 riod. 



Average incubation period . 



Maximum 



Minimum J. 



10 



11 



12 

 7.5 

 8.5 

 9.5 



10.5 



11.5 



12.5 



10 



12 



15 



Total 



days. 



860 

 110 



12 



13 



16 



132 



108 



12S 



9 



60 



55 



24 



90 

 263.5 



76 



220. 5 

 184 

 100 



40 



36 



30- 

 342 



45 



30 



2,984 



9.9 

 . 16 

 6 



Length of life of first-brood larvse by instars. — Seventy larva; from 

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

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

 19 parthenogenetic larvse, and a complete record of 8. Table VI 

 gives a summary of the length of larval life by instars, of all larvae 

 reared. 



