6 INSECTS INJURIOUS TO SUBTROPICAL FRUITS. 



long as I and II combined and about twice as long as wide; IV about as long 

 as III. tapering to obtuse apex. Wing-pads extending to distal margin of the 

 second abdominal segment, those of hind wings slightly longer. Legs stout, 

 hind femora and tibiae about equal. Hairs present on live specimens but not 

 prominent, short, slightly longer on tip of abdomen. 



Second-stayc pupa. — Length 0.G6G mm. ; width of head 0.133 mm. ; width of 

 prothorax 0.133 mm. ; width of mesothorax 0.1G6 mm. ; width of abdomen 0.133 

 mm. Shape similar to that of the adult. Color translucent white to pale yel- 

 lowish ; eyes reddish, more prominent than in first-stage pupa. Antennre 4-seg- 

 mented, projecting backward over the head and thorax and reaching to the 

 middle of the prothorax, second segment forming a kind of elbow from which 

 3 or 4 long set;e project cephalad. Prothorax nearly twice as broad as long; 

 wing-pads in pupae just entering the second pupal stage extending to the 

 distal margin of the sixth abdominal segment ; in pupte in which the adults 

 are nearly ready to emerge the wing-pads extend to the distal margin of the 

 ninth abdominal segment. Abdomen similar in shape to that of the adult. 

 Legs stout, hind femora and tibi;ip about equal in length, setae more prominent 

 than in first-stage pupa, longer at the tip of the abdomen ; conspicucuit in fresh 

 specimens but not in mounted ones. Tip of abdomen often with a cremaster- 

 like formation resembling in shape a fork with 4 tines. Male pupae smaller, 

 resembling the adults, their wing-pads usually reaching past the tip of the 

 abdomen. Setae usually not so prominent. 



SEASONAL HISTORY. 



The orange thrips passes the Avinter in the adult state, and it is 

 generally the adult form which first becomes conspicuous upon the 

 orange trees in the spring. Although no large number of adults 

 has been collected in hibernation, these undoubtedly pass the winter 

 in sheltered places, such as the dead leaves and twigs forming the 

 trash under most orange trees; they are occasionally found on living 

 plants and on citrus nursery stock in midwinter. 



Adult thrips appear in limited numbers during March. They 

 deposit very few eggs in the early part of April, prior to the blossom- 

 ing of the Navel orange trees, but soon after most of the petals have 

 fallen larva? become quite numerous. Oviposition has not been 

 observed, but it is probable that it takes place mostly at night. 

 Examinations for eggs revealed the fact that most of them are placed 

 in the new, tender growth, being inserted into both upper and lower 

 leaf surfaces, and also in the shoots. They are also placed in the 

 receptacles of the blossoms after the petals have fallen and in young 

 fniit and fruit stems. 



The larva^ are wingless and wdien full grown are orange colored. 

 When ready to jDupate they fall from the trees, get into a curled dead 

 leaf, amid cobwebs, dust, and leaf particles, and hide until the trans- 

 formation is completed. Pupa? are not found in numbers propor- 

 tionate to the larva^ and adults, since it is in this stage that the 

 mortality rate of the insect is greatest. The pupa> are very soft- 

 bodied and less active than larvae and adults. They move readily, 

 however, when disturbed. 



