8 



BULLETIN 1225, U. S. DEPARTMENT OF AGRICULTURE. 



PREPUPA. 



Average measurements of the prepupa (PI. I, E) are: Length 2.27 mm., width of 

 mesothorax 0.537 mm. Somewhat smaller than the preceding stage and lighter in 

 color. The blotches of pigment now appear larger and not so numerous throughout 

 the body, which is whitish or almost transparent. The head and thorax are white, 

 with little coloring except for the eyes, which are larger and reddish brown. The 

 last abdominal segment is light brown. The legs are colorless and the antennae, 

 which are short, heavy, and folded back along the head, are also colorless. The wing 

 pads show as short colorless sacs. Numerous long whitish hairs appear on the antennae 

 and abdomen. 



PUPA. 



Average measurements of the pupa are: Length 1.98 mm., width of mesothorax 

 0.417 mm. The pupa (PI. I, F) is smaller than the prepupa, but similar in color, 

 except for the presence of a little more pigment, particularly in the head and thorax. 



The antennae are now longer but folded back along 

 the head. The wing pads are longer, reaching 

 ; S • about the third abdominal segment. Numerous 



long white or colorless hairs are on the legs, anten- 

 nae, and abdomen. 



— -COTTOAS 



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 T/?£T£- 



MALES. 



In the larval and pupal stages the males 

 are somewhat smaller than the females 

 and have a distinct purple color, but 

 otherwise are similar in structure and 

 appearance. They occur very rarely in 

 nature. 



LIFE HISTORY AND HABITS. 



METHODS OF REARING. 



The life history of the camphor thrips 

 was worked out in the laboratory under 

 conditions as nearly natural as possible, 

 with daily observations on the insects 

 infesting growing trees. The work was 

 carried on in summer and also during the 

 cooler weather of winter. Test tubes 

 were employed as breeding cages and the 

 thrips confined on small pieces of camphor 

 twig. (Fig. 6.) The twigs were cut in 

 lengths of about 3 inches and placed in 

 water in small shell vials, the mouth of 

 the vial being filled with cotton which 

 surrounded the twig and held it in place. 

 This vial was then dropped into a test 

 tube and the test tube stoppered with 

 cotton. The immature stages of the 

 thrips were usually held on the camphor twigs by the cotton, 

 but should one succeed in crawling over the cotton it was confined 

 inside of the test tube and could be replaced on the twig. The adults 

 would fly across on to the test tube, but would return to the twigs to 

 feed and oviposit. In all experiments fresh food was given the thrips 

 every few days and they were kept until they died a natural death. 

 Owing to the activity of the thrips and their small size, some of Jk 

 them were lost or injured in transferring to new cages or new food. 



--COTTOA/ 



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— COTTOA/ 



Fig. 6, 



-Test tube used as a breeding cage 

 for the camphor thrips. 



