THE GREENHOUSE THRIPS. 



In the case of infested plants, injuiy is noticed first to the older 

 leaves and gradually, as these become badly infested, the injury 



Fig. 4.— Portion of leaf of croton magnified to show pupae of greenhouse thrips. (uiigiual.) 



spreads until the young leaves are attacked, soon after unfolding. 

 The infested leaves first show injury on the underside, where the 



