EXPERIMENT STATION BULLETINS. 



283 



not thrive in wet weather, on the other hand requiring hot, dry con- 

 ditions for their best good. Fortunately, rain came in time to save the 

 greater part of the crop, many of the thrips dying off and their depreda- 

 tions diminishing. 



Fig. 3. — Work of Thrips on leaves of Oats, enlarged. Original. 



Fig. 4. — Work of Thrips on leaves of Oats, enlarged. Original. 



Kecovery from the injury was fairly rapid in fields where the 

 grain was headed out and where the leaves were unfolded; the 

 water seeming to wash off the pests except a few that succeeded in 

 gaining shelter in the axils of the leaves. The younger plants, on the 

 other hand, retained their quota of the insects longer, owing to their 

 habit, as Mr. Kraus discovered, of hiding in the crevice left by the 

 unrolling of the leaf blade. Here they would work inward as the leaf 



