414 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



being very conspicuous on the light green shoots of the camphor. 

 The bark where these groups of larvae feed is killed (Plate 11, figure 3), 

 and, as it dries out, it cracks (Plate 11, figure 4). The adults use 

 these cracks as hiding places and as a means of entrance to the cambium 

 on which they lay their eggs. As the infestation proceeds the bark on 

 all of the twigs is killed and the leaves are shed. This leaves the cam- 

 bium as the only suitable breeding place, and here the larvae as well 

 as the adults are to be found. A favorite feeding place is at the base 

 of a branch. This is quickly killed and then easily broken off, leaving 

 a scar much like the one at the base of a petiole only larger and deeper 

 (Plate 11, figure 5). They also gain access to the cambium at the cut 

 ends of the twigs after the trees have been pruned to supply material 

 for distillation. The Cryptothrips continue to work on the cambium 

 until the whole plant is killed. The insect seems to be incapable of 

 flight, although it has well developed wings. It probably spreads 

 from one plant to another by means of workmen and horses which 

 brush against the plants during cultivation, and by crawling over the 

 ground, leastwise it spreads in all directions from the center of in- 

 festation, but most readily along the rows, where the distance between 

 the plants is less than that across the rows. It kills every plant in 

 its onward march, although it may temporarily skip one to attack 

 those beyond. 



It was found on large trees at Satsuma, near Palatka, and at Tampa, 

 but seems to do very little harm to them. It is the young seedlings 

 in the nursery row and the young trees in the field that are killed. 

 The writer has been unable to find this insect about Jacksonville, 

 Gainesville, or other towns in north Florida. This raises the question 

 of its origin. The camphor is not a native of Florida. Is this insect 

 a native species which has spread to the camphor, or has it been im- 

 ported with camphor? The writer will be very grateful if entomolo- 

 gists located where the camphor trees grow will send him specimens 

 of any black (larval yellow) thrips found on this tree. 



Tobacco decoctions kill them, but it has been found necessary to 

 make them stronger than for most species. For the adults a solution 

 composed of a half gallon of whale oil soap, one half gallon of com- 

 mercial lime sulphur, and a half pound of Black Leaf 40 to fifty 

 gallons of water is now in use. This has proven quite efficient. It 

 does not, however, kill the eggs and of course all the adults and larvae 

 hidden under the bark escape. By spraying not later than the stage 

 represented in figure 3 when the larvae are mostly in the buds or on 

 the outside of the twigs, and by cutting out the trees in the later 

 stages of infestation, it was found possible to control this pest. 



