16 
BULLETIN 1225, U. S. DEPARTMENT OF AGRICULTURE. 
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 — Con. 
IN WINTER. 
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 
of post- 
oviposi- 
tion 
period. 
Total 
length 
of life. 
Total 
num- 
ber of 
eggs 
laid. 
1 
1920-21. 
Dec. 1 . . . 
Nov. 8... 
Nov. 12.. 
Nov. 17.. 
Dec. 28.. 
Dec. 30.. 
Jan. 2... 
Jan. 7. . . 
...do.... 
Jan. 12. . 
Jan. 26. . 
Jan. 29.. 
Feb. 9... 
Feb.l... 
Feb. 14.. 
Feb. 6... 
...do.... 
Feb. 8... 
Feb.6... 
Feb. 8... 
1920-21. 
Dec. 8... 
Nov. 14.. 
Nov. 17.. 
Nov. 22.. 
Jan. 7. . . 
Jan. 6... 
Jan. 9... 
Jan. 13.. 
Jan. 15. . 
Jan. 22.. 
Feb. 3... 
Feb. 8... 
Feb. 18.. 
Feb. 8... 
Feb. 25.. 
Feb. 11.. 
Feb. 14.. 
...do.... 
Feb. 11.. 
Feb. 16.. 
Days. 
7 
6 
5 
5 
10 
7 
7 
6 
8 
10 
8 
10 
9 
7 
11 
5 
8 
6 
5 
8 
1921. 
Mar. 12.. 
Mar. 18. . 
Apr. 3... 
Feb. 7... 
Mar. 26.. 
Apr. 26.. 
Mar. 19.. 
Apr. 7... 
Jan. 25. . 
Apr. 3... 
May 10. . 
Mar. 20.. 
Apr. 29.. 
Mar. 26.. 
Apr. 9... 
June 4... 
Mar. 19.. 
Apr. 24.. 
Mar. 20.. 
Apr. 11.. 
Days. 
94 
124 
137 
77 
78 
110 
69 
84 
10 
71 
96 
40 
70 
47 
43 
113 
33 
69 
47 
54 
1921. 
Mar. 14.. 
Mar. 19.. 
Apr. 4... 
Feb. 8... 
Mar. 28.. 
Apr. 28. . 
Mar. 21.. 
Apr. 9... 
Feb. 4... 
Apr. 5... 
May 11.. 
Mar. 21.. 
Mavl... 
Mar. 28. . 
Apr. 9... 
June 6... 
Mar. 20. . 
Apr. 25.. 
Apr. 3... 
Apr. 16.. 
Days. 
2 
1 
1 
1 
2 
2 
2 
2 
10 
2 
1 
1 
2 
2 

2 
1 
1 
14 
5 
Days. 
103 
131 
143 
82 
90 
119 
78 
92 
28 
83 
105 
51 
81 
56 
54 
120 
42 
76 
56 
67 
Eggs. 
365 
2 
489 
3 
348 
4 
211 
5 
219 
6 
7 
117 
8 
405 
9 
10 
25 
320 
11 
401 
12 
144 
13 . 
251 
14 
253 
15 
341 
16 
553 
17 
18 
154 
404 
19 
260 
20 
327 
7.4 
73.3 
2.7 
82.85 
307 
1 
PARTHENOGENESIS. 
Reproduction of the camphor thrips seems to be almost entirely 
by parthenogenesis. No males have ever appeared in the breeding 
jars at any time of the year. Occurring in nature rather rarely, it 
is doubtful if the males fulfill any necessary role in the propagation 
of the species. Large numbers of the adults captured from trees 
and placed together in jars have never shown any tendency toward 
mating. The fact that isolated females have been reared for many 
successive generations proves that they can reproduce throughout 
the year parthenogenetically. The male larvas, which are rather con- 
spicuous because of their purple coloring, were found most abundant 
in January on the trees in the laboratory yard. Some occurred 
throughout the spring and until June, but none were seen during 
the summer. These larvae when raised to adults in jars and placed 
together with recently matured females were never seen to mate. 
Neither did these females produce any offspring which showed any 
purple color like the immature males. In fact a purple larva never 
was produced in any of the life-history work. 
FLYING HABITS. 
Although provided with fully developed wings, the thrips seldom 
fly, and flight is a small factor in the distribution of the species. 
The maximum flight which has been observed was only a few feet. 
Watson {2) also states that the thrips seem to be incapable of flight. 
On a few occasions adult thrips were seen to fly from one limb to 
another, but it is very doubtful if they ever attempt any long flight, 
such as from one field of camphors to another, and seldom even from 
one tree to another. In the breeding jars the adults often fly from 
the camphor limb to the sides of the jar, and on one occasion a 
