ANIMALS INJURIOUS TO FRUIT TREES. 



21 



produce a second generation ; but to his certain knowledge adults of 

 a second generation did not appear on the trees. The nymph is active 

 at all times. \Yings develop from mere buds to long sacs, which pro- 

 ject backward along the sides of the body, and 

 eventually reach beyond the tip of the abdomen. 

 The Adult. "The adult thrips (Fig. 9) 

 remain in the pupal stage chamber for days, 

 and it may even be weeks before they issue 

 forth to take up active life. How individual 

 thrips force their way through the several 

 inches of earth which lies above them is still 

 a question. They come out, it seems, only 

 after the ground has been thoroughly softened 

 by rains, and it is evident, too, that they 

 depend largely on the natural openings. They 



cannot possibly use the backwardly bent FlG .THE PEAR THRIPS 

 mouth cone as a means of boring or biting Head and prothorax from side, to 

 their way out. They have several groups of show mouth-parts. Much enlarged. 



(After Moulton). 



spines and certain angular edges on the sides 



of the abdominal segments, however, which might be used in forcing a 

 way through the soft soil. They also possess roughened scoop-like 

 structures parts of the chitinous, hoof-like shell of the feet which 

 undoubtedly are used for digging." 



FIG. io. THE PEAK THRIPS. Fore wing of female. Much enlarged. (After Moulton). 



PREVENTIVE AND REMEDIAL MEASURES. 



Seeing that this insect spends most of its life in the ground, and 

 is well protected during the short period it is on the trees, spraying 

 is of little use. 



Deeply turning over the surface soil wherever possible would 

 seem to be the most practical remedy. 



