THE CITRUS THRIPS. 
17 
Table V. — Seasonal variations in duration of the pupal stage of the citrus 
thrips, Lindsay, Cal., 1911. 
Period of season. 
Apr. 8 to Apr. 26.. 
May 3 to May 13.. 
May 22 to June 4 . . 
June 2 to Sept. 5 . . 
Aug. 31 to Sept. 26 
Sept. 21 to Oct. 28. 
Oct. 18 to Dec. 2.. 
Prevailing 
mean tem- 
peratures. 
56.52 
58.08 
64.74 
76.55 
68.20 
60.70 
51.04 
THE ADULT. 
DESCRIPTION. 
The adult citrus thrips (fig. 8) is among the smallest of insect pests 
and is smaller than most of the more injurious related Thysanoptera. 
The female measures from 0.60 to 0.88 mm. (about one-fiftieth to 
one-twentieth inch) in length; the male, which is noticeably smaller, 
measures from 0.51 to 0.65 mm. The color of the adult is translucent 
Fig. 8. — The adult female citrus thrips. Highly magnified. (Original.) 
orange-yellow; the male is somewhat paler than the female. The 
head is small, about one-half as long as wide, and a considerable por- 
tion of it is occupied by the large compound eyes, which are dark 
purple to black. Three transparent ocelli, or simple eyes, bordered 
by reddish brown crescents, occupy the space between the compound 
eyes on the upper surface of the head. The antennas are 8- jointed ; 
some of the segments are furnished with transparent sense organs. 
