222 Bugs, Cicadas, Aphids, and Scale-insects 



grown in five days, and the quiescent pseudo-pupal stage lasts four days. 

 The grass- thrips is the cause of the injury or disease of meadow and pasture 

 grasses known as "silver top" or "white top," a common trouble in the 

 northeastern states. The male sex seems to be wanting in this species, the 

 young all developing parthenogenetically. The orange thrips is about one- 

 thirtieth of an inch long, orange-yellow in color and capable of very rapid 

 movements by running, leaping and flying. So far as yet known it is limited 

 to California and Arizona. In California it is a serious pest in the orange 

 belt of the San Joaquin valley. It has not yet been found attacking oranges 

 in Southern California. The pear thrips, which was discovered in 1904 

 in California, has become one of the most serious pests of the deciduous 

 fruits of that state. It is especially abundant in the valuable prune and 

 apricot orchards of the counties bordering San Francisco Bay. It also 

 does much injury in the Sacramento valley. It attacks almonds, apricots, 

 cherries, peaches, pears, plums, prunes and other fruits. It appears in the 

 early spring just as the flower buds are opening, and after feeding on the 

 tender flower parts, it lays its eggs from which young soon hatch that feed 

 upon the young leaves and fruit. By the first of May all these young drop 

 to the ground and burrow a little way underneath the surface. Here they 

 lie slowly growing and developing all through the summer, autumn and 

 winter, issuing as winged adults in the following spring. 



