]20 MISCELLANEOUS PAPERS. 



The writer recently visited a packing house where oranges from 

 thrips-infested orchards were being graded and boxed, and found 

 that about 30 per cent were passed from fancy (first grade) to choice 

 (second grade) , which means a difference in price of about 40 cents 

 per box : and that about 5 per cent of the crop was being passed out 

 as culls, due entirely to the scablike markings of the thrips. While 

 the quality' of the fruit is not noticeably impaired, as the injury is 

 present only on the surface of the skin, oranges are graded and also 

 sold largely on appearance, and this scab produces a very unpresent- 

 able fruit. (See PL VIII, figs. 3, 4.) 



The thrips feeds also on the foliage and tender branches, and the 

 damage to these is serious, although not so noticeable as on the fruit. 

 Only newly unfolding and tender leaves and buds are attacked; as 

 the feeding is mostly confined to the surface no part of the leaf tissue 

 is killed outright, but there folloAvs the '' silvering," characteristic of 

 thrips and other surface-feeding insects. The leaves become cup- 

 .'haped and wrinkled and the tissues noticeably thickened. (PI. VIII, 

 figs. 1, 2.) Orange trees in this section have four growths annually, 

 so that there is always an abundance of new foliage present when the 

 thrips is above ground. 



LIFE-HISTORY NOTES. 



There are apparently two broods of this species. Adults of the 

 first brood appear just before the blossoms in February, March, and 

 April, and a second brood appears in July, August, September, and 

 October. xVdults and larva? of the first brood feed on the small 

 oranges just as the petals are being thrown off, the larvae usually 

 under the protection of the sepals, and on the first growths of the 

 foliage. The second brood feeds on the nearly mature oranges and 

 on the third and fourth growths of the foliage. All varieties of 

 oranges and lemons are attacked, but the very noticeable scabbing 

 on the fruit is common only on the navel orange ; it is less conspicuous 

 on the Valencia. 



SOIL CONDITIONS AS AFFECTING PREVALENCE. 



It has been noticed that the thrips is not so prevalent on trees 

 planted in sedimentary or loam soils as where the soil is of a clayey 

 or adobL' texture. This fact may be explained as follows: This 

 thrips, like most others of its group, presumably spends the last of 

 its larval, its pupal, and its early adult life in the soil underneath 

 the trees, and would naturally, then, be more or less affected by the 

 texture of the soil and by cultivation. Orange groves are usually 

 irrigated several times during the summer and are cultivated 

 throughout the year. Sedimentary soils break to pieces readily 



