ENTOMOLOGY 127 



control this species in normal seasons with four applications of lime- 

 sulphur combined with blackleaf tobacco extract. 



Three of the treatments should be made in the spring to free 

 the fruit and spring growths of foliage from injury, since the more 

 severe marking of fruit is done while the fruit is small. The fourth 

 treatment should be made in August or September, according to 

 season, for the protection of the later growths of foliage, and should 

 be timed to catch the thrips when numerous, but before the leaves 

 show much curling. The three spring applications should be made 

 about as follows: First. Just after most of the petals have fallen 

 from the blossoms; Second. Ten to fourteen days after the first; 

 Third. From three to four weeks from the time of the second treat- 

 ment. The dates for spraying in any given season must be timed 

 by the abundance of thrips. (U. S. D. A., B. E. Bui. 99, Part I.) 



The Red Spider of Citrus Trees. Red spiders have been in- 

 jurious in southern California for many years, but little attention 

 has been given to the matter, chiefly on account of the extremely 

 minute size of these creatures. The appearance of the fruit from 

 trees badly infested with the red spider is very characteristic, and 

 easily recognized when once known, but has not, as far as we can 

 learn, been taken into consideration in the grading of fruit. Should 

 the market come to recognize and begin to discriminate against the 

 paler fruit, upon which the mite has been at work, the lasses would 

 become very large. 



Upon hatching, the creature which appears resembles the adult 

 mite very closely except in size and in the absence of the hind pair 

 of legs, making the number six, thus resembling insects to this 

 extent. Many other mites are six-legged ' when first hatched from 

 the egg. The young red spider at once begins to feed and is very 

 soon ready to prepare for the change of skin which results in the 

 assumption of the fourth pair of legs. The juices of the leaf are 

 sucked up through a tube-like cavity between the palpi ; and where 

 each slit is made and the contents pumped out a paler spot remains. 



A material that is both safe and effective is the sulfid of potash 

 spray mixture. This mixture is usually made according to the fol- 

 lowing formula: 



Potash 32 Ibs. 



Sulphur, finely ground 37 Ibs. 



Salt 2 Ibs. 



Water 50 gal. 



This makes the stock-solution which is diluted with about a 

 hundred times as much water for spraying. The potash, sulphur, 

 and salt may be mixed together in a large metal tub with a little 

 water, when chemical action will at once set in and the whole mass 

 will dissolve and begin to boil very vigorously. After the boiling 

 has ceased, the water is added and the stock-solution is made. It 

 is very doubtful whether the salt is of any value in this mixture, but 

 it can at least do no harm as it is in such small quantity. This 

 sulfid of potash is of very little value, at least at this strength, as an 

 insecticide, but is effective enough against the active stages of the 



