The White Flies or Aleyrodtds 



in any northern greenhouse in which orange or lemon trees 

 occur. It is found in the south also upon the china-berry tree, 

 upon viburnum, cape jessamine and the water oak. The follow- 

 ing life history account is drawn up from observations made in 

 greenhouses in the city of Washington. The insect passes the 

 winter in the full-grown larval condition. The adult insects issue 

 during April and begin to lay their eggs about or before the 

 middle of the month. About twenty-five eggs are laid by each 

 female. The eggs are very delicate, pellucid, and each possesses 

 a slender petiole or foot-stalk about one-third the length of the 



Fig. 141. — Aleyrodes citri. (From hisect Life.) 



egg proper. In two weeks the young larva hatches. It is com- 

 paratively active and crawls a short distance from the egg-shell 

 before beginning to feed. In from two to four weeks it molis 

 and by the middle of June three skins have been cast. In molt- 

 ing the insect curves the abdomen upwards at more than right- 

 angles, moving it occasionally up and down. It shrinks away 

 from the side margin until it occupies only about one-third of the 

 original lateral space. The skin then splits at the anterior end or 

 underneath the head. Then the head and prothorax are pushed 



248 



