6 BULLETIN 1225, U. S. DEPARTMENT OF AGRICULTURE. 



to grow unhindered they attain great size and become remarkably 

 beautiful (fig. 4). 



When grown for ornamental hedges along streets or in dooryards, 

 however, where it is necessary to keep the trees pruned back regularly, 

 they suffer considerable damage from the thrips. They suffer also 

 when the trees are cut back to procure material for distillation. The 

 insects collect in great numbers around the cut ends and feed upon 

 the plant tissues. In addition they destroy the buds (PL II) and 

 new growth when put forth by the trees, and even work in the 

 limbs (PL III), causing the bark to crack (PL IV, A) and later the 

 limbs to become deformed (PL V). Their chief damage is probably 

 to the buds, and when present in any great number they prevent 

 the trees from putting forth very much new growth, without which 



Fig. i.— Row of camphor trees planted as a windbreak for a citrus grove. When uninjured the trees make 

 a beautiful hedge and are not seriously attacked by the camphor thrips. 



camphor production is cut off. As will be shown later; the usual 

 pruning practices had to be changed. Instead of pruning the trees 

 promiscuously and cutting the limbs back to stubs it was found 

 necessary to cut the trees off at the level of the ground. 



DESCRIPTION. 



I, A) was by Prof. J. R. 



ADULT. 



The original description of the adult (PL 



Watson {1), as follows: 



Cryptothrips floridensis, new species. 



Measurements: Head, length 0.25 mm., width 0.20 mm.; prothorax, length 0.17 

 mm., width 0.34 mm.; mesothorax, width 0.40 mm.; abdomen, width 0.44 mm.; 

 total length of insect, exclusive of antennae, 1.89 mm.; tube, length 0.14 mm., widtbf 

 at base 0.075 mm.; antennae, 1, 36 m; 2, 51.7 n; 3, 77.6 m; 4, 78 m; 5, 65 m; 6, 63 m; 7, 

 54.5 m; 8, 40 m; total 0.42 mm. 



General color, black, no purple pigment; tarsi dark brown and antennae yellow. 



