THE CITRUS WHITE FLY: LIFE HISTORY AND HABITS. 67 
of the abdomen, curved gently upward and inward, each bearing 4 or 5 equidistant 
minute cylindrical piliferous tubercles on upper and outer edge; style almost as long 
as claspers, rather stouter at base, more slender toward tip, terminating in a stout spine 
at upper end. Head and abdomen with heavy tufts of wax soon after issuing from 
pupa. 
Examination of a large number of antennae shows that the relative 
length of the antennal segments is subject to slight variations. The 
average relative lengths are about as follows: 
Segment A A A A A A A Spine. 
10, 24, 43, 16, 16, 18, 22, 3 
Although they have examined thousands of males both at and for 
some time after emergence and as they occur at all times throughout 
the grove, the authors have never been able to observe males with the 
tufts of wax on head and abdomen mentioned in the above descrip- 
tion and illustrated in connection with its original publication. 
EMERGENCE. 
DESCRIPTION OF THE PROCESS. 
The emergence of the adult occurs soon after its purple eyes and 
folded whitish wings can be seen distinctly through the pupal skin. 
About 20 minutes before the pupal skin is ruptured the body of the 
adult shrinks gradually away from it and assumes its natural shape. 
This gradual shrinking away from the edges of the pupa, and the 
accompanying thickening of the body, brings a pressure to bear on 
the pupal skin which causes it to split from margin to margin between 
the thorax and abdomen and along the median line from this 
rupture to the anterior margin. Through the T-shaped opening 
thus formed the insect first pushes its thorax, then its head, with 
little apparent exertion. The body now projects almost perpendicu- 
larly from the pupa case, as the pupal skin is called, with the an- 
tennas, legs, and abdomen still in their pupal envelopes. By a series 
of backward and forward movements the antennae and legs are freed 
from their membranes and are in constant motion. The abdomen is 
now so nearly out of the pupal case that the fly is practically free, 
holding on only by means of the end of the abdomen. With a sudden 
forward bend of the body the legs are brought in contact with the leaf, 
and with their aid the fly frees the rest of its abdomen and crawls 
away rapidly. 
The period covered between the time the insect ruptures the pupal 
skin and the time it becomes entirely free from the case and is crawl- 
ing is from 7 to 10 minutes. Not infrequently flies die during 
emergence. 
1 These represent the spaces read on eyepiece micrometer when 1-inch eyepiece 
and ^-inch objective are used, and the miscroscope tube is drawn to 160. 
