THE CAMPHOR THRIPS. 



15 



tip as the egg moved along, the egg easily slipping out when it reached 

 the end. The female immediately crawled away without looking at 

 the egg. On another occasion a female crawled up to the top of a 

 limb in a jar and immediately deposited an egg on the cut surface. 

 Then she at once crawled away, the entire operation requiring no 

 more than 30 seconds. 



Rate of ovivosition and number of eggs laid. — The rate of oviposition 

 is dependent to a considerable extent on the weather. Many more 

 eggs are laid on bright warm days than on cloudy or cold days. 

 The average for 20 individuals in summer was 5.1 eggs per day 

 throughout the egg-laying period, while in winter there was an 

 average of 4.19 per day for 20 individuals. After a brief preoviposi- 

 tion period amounting to 3.2 days on the average in summer and 7.4 

 days in winter, the females begin egg laying. The number of eggs 

 laid per day has varied from none up to 13 in one case, but will average 

 about 4 or 5. As vail be noted in Table 3, some females are much 

 more productive than others, even when kept under identical condi- 

 tions. In the breeding jars some insects have laid from 7 to 10 or 11 

 eggs per day over a considerable period. Toward the end of their 

 life the number of eggs per day diminishes, and finally ceases, being 

 followed by a brief postoviposition stage. This period of inactivity 

 varied from 1 to 14 days, with an average of 4.4 days for summer 

 and 2.7 days for winter. The average length of the egg-laying stages 

 was 90.4 days and the average total number of eggs 463.7 in summer. 

 For winter the average of the egg-laying stages was 73.3 and the 

 average total number of eggs 307. The greatest number of eggs laid 

 hy an individual thrips was 684. 



Table 3. — Length of life of adults of the camphor thrips, showing length of egg-laying, 

 preoviposition, and postoviposition periods, together with number of eggs laid. 



IN SUMMER. 



Record No. 



Date 



adult 

 emerged. 



Date 



first egg 



laid. 



Length 

 of pre- 

 oviposi- 

 tion 

 period. 



Date 



last egg 

 laid. 



Length 

 of egg- 

 laying 

 period. 



Date of 

 death. 



Length 

 ofpost- 

 oviposi- 



tion 

 period. 



Total 

 length 

 of life. 



Total 



num- 

 ber of 

 eggs 

 laid. 



1 



1921. 

 Aug. 22.. 

 Aug. 23.. 

 Aug. 22 

 Aug. 23 

 Aug. 24.. 

 ...do 



1921. 

 Aug. 25.. 

 Aug. 26.. 



do.... 



do.... 

 Aug. 27- 

 ...do 



Days. 

 3 

 3 

 4 

 3 

 3 

 3 

 4 

 3 

 3 

 3 

 3 

 5 

 4 

 3 

 3 

 3 

 2 

 3 

 3 

 3 



1921-22. 

 Oct. 24... 

 Nov. 26.. 

 Nov. 3... 

 Oct. 24. . 

 Oct. 29.. 

 Oct.l... 

 Dec. 20. . 

 Oct. 4... 

 Dec. 27.. 

 Oct.14.. 

 Dec. 15 — 

 Mar. 4... 

 Dec. 27. . 

 Jan. 3... 

 Oct. 29. . 

 Jan. 23.. 

 Nov. 10.. 



Jan.5 



Dec. 16.. 

 Oct.21.. 



Bays. 

 60 

 92 

 69 

 59 

 63 

 35 

 115 

 38 

 122 

 48 

 109 

 187 

 120 

 127 

 61 

 147 

 72 

 128 

 108 

 48 



1921-22. 

 Oct. 26.. 

 Nov. 30- 

 Nov. 5... 

 Oct. 26.. 

 Oct. 31.. 

 Oct. 4... 

 Dec. 23.. 

 Oct.8... 



Jan. 3 



Oct. 21.. 

 Dec. 19. . 

 Mar. 8... 



Jan. 9 



Nov.l... 

 Feb. 2... 

 Nov. 16.. 



Jan. 9 



Dec. 19 . . 

 Oct. 26.. 



Days. 

 2 

 4 

 2 

 2 

 2 

 3 

 3 

 4 

 7 

 7 

 4 

 4 

 7 

 6 

 3 



10 

 6 

 4 

 3 

 5 



Days. 

 65 

 99 

 75 

 64 

 68 

 41 



122 

 45 



132 

 58 



116 

 96 



.31 



136 

 67 



160 

 80 



135 



114 

 56 



488 



2 



559 



3 



484 



4 



434 





360 



6 



280 



7 



Aug. 23.. 

 Aug. 24 

 ...do 



...do 



do.... 

 ...do 



496 



8 



242 



9 



656 



10 



11 



...do 



Aug. 25.. 

 Aug. 24.. 

 Aug. 25 

 Aug. 26 

 ...do 



...do 



Aug. 28.. 

 Aug.29- 



do 



do 



...do....- 



136 

 516 



12 



684 



13 



465 



14 



508 



15 



430 



16 



...do 



...do 



672 



17 



Aug. 28.. 

 Aug. 27.. 

 ...do.... 



Aug. 31.. 



Aug. 30- 

 ...do.... 

 ...do 



Sept. 3. . 



521 



18 



578 



19 



20 



538 

 227 







Average 



3.2 





90.4 



4.4 



98 



463. 7 i 































4 



