4 FARMERS’ BULLETIN 674. 
oranges were shipped in 1911. The approximate average number of 
boxes of fruit to the car is 390, making 594,750 boxes for the season’s 
shipment. From examination of thousands of oranges in the field, 
throughout the district and in many groves, it was calculated that 
34 per cent of all the fruit would be classed as first grade so far as 
thrips injury was concerned, 43 per cent as second grade, and 23 per 
cent as third grade. Returns received by different packing houses 
on a total of 358,000 boxes of navels of all grades for the season in- 
dicated the following average differences in price per box between the 
different grades. First-grade fruit averaged 37 cents more per box 
than that of second grade; the latter 28 cents more than that of third. 
Fruit shipped in only two grades gave an average difference of 51 cents 
per box in favor of the first grade. _It may be seen from the foregoing 
data that 43 per cent, or 255,742 boxes, of the Lindsay fruit was re- 
duced to second grade at a loss of 37 cents per box, or $94,624.54; 
23 per cent was reduced to third grade at a loss of 65 cents per box, or 
an additional $88,914.80. There was thus a total loss for the Lindsay 
district alone of approximately $183,539.34 in the season of 1911 
from grade reduction caused by thrips. 
SUMMARY OF SEASONAL HISTORY. 
In seasons such as 1911, adult citrus thrips first appear in April and — 
increase rapidly during April and May, during which time the insects 
are congregated largely on the fruit and foliage of the orange. During 
part of June, July, and August the adults leave the toughening fruit 
and leaves of the orange and disperse over miscellaneous food plants, 
and it is during this period of wider separation that mating and 
oviposition are somewhat checked. In August and September there 
is a series of flights back to the late summer growths of the orange, 
where the insects concentrate in large numbers, mating and actively 
depositing the eggs which produce the insects of the following spring. 
The citrus thrips begins to disappear about the middle of October, 
and after December practically none can befound. There are generally 
afew larvee and adults in places on the trees until the early part of Jan- 
uary, at which time they disappear completely. The eggs which are 
deposited in the stems and leaves of the orange in the fall mostly pass 
the winter successfully, hatching during the ensuing March, April, and 
May. The seasonal activities of the citrus thrips, as related to orange 
blossoming, growth periods, and spraying are summarized graphically 
in figure 3. 
SUMMARY OF LIFE HISTORY. 
There is a tendency on the part of the citrus thrips to breed through- 
out the year. All stages of the insect are found on the trees through- 
out November and December. Larve, pup, and adults gradually 
