THE CITRUS WHITE FLY: LIFE HISTORY AND HABITS. 
61 
are very distinct. As the pupa becomes older it becomes thicker, 
more rounded and opaque, and the outlines of the legs are obscured 
by the contents of the body. At the approach of maturity a bright 
red or orange spot develops on the back, and from three to eight days 
before emergence the eyes of the adult become visible. A detailed 
description is as follows : 
Length, 1.10 mm to 1.40 mm; width, 0.60 mm to 1.0 mm. Body broadly elliptical, 
thin, not raised from leaf on vertical wax fringe, color pale yellowish-green, becoming 
more yellowish and thicker on approaching maturity; thoracic lobes, representing out- 
lines of the three pairs of legs, and a line extending from between first two pairs of 
legs and from the vasiform orifice to edge of body distinctly more yellowish, as are also 
the lines representing the union of the body segments although these last are promi- 
nent. As body thickens thoracic lobes become less distinct due to body contents, a 
bright orange or red medio-dorsal spot develops 
at anterior end of abdomen, and later, a few 
days before emergence, the purple eyes of adult 
become very distinct, as also do the white devel- 
oping wing pads; rim of vasiform orifice brown or 
yellowish. All marginal bristles lost except one 
anterior and one posterior pair of minute bris- 
tles. A low medio-dorsal ridge or carina and 
corresponding depressions on each side extend 
from the head to the anal ring, traversed by short 
transverse ridges on the thorax and abdomen, 
terminating in a low subdorsal ridge hardly per- 
ceptible; from these last numerous very fine 
granulated striae radiate all around the body to 
the lateral margin. A short transverse ridge 
appears near posterior margin of head with a 
curved impressed line in front. A minute brown 
tubercle at the anterior end of the subdorsal 
carina is sometimes to be seen. From a pore at the edge of the body, between head 
and thorax and top of anal slit, issues a very fine, glistening- white, curled thread 
of waxen secretion. These so-called "pores" in margin of the cephalo-thoracic 
region are formed by a slight upfolding of the body which extends from margin to 
cephalo-thoracic spiracle and forms an outlet for secretions from same. Location of 
spiracles and respiratory system as already described for aleyrodids. Legs and 
antennae easily seen with high-power lens. Antennae located as shown in fig. 9, 
partially concealing front pair of legs, apparently 3-segmented but division into seg- 
ments not distinct; last segment as long as other two combined, with quite a number 
of irregular annulations; tip provided with a stout spine. Legs short, very stout, 
especially the two posterior pairs; front legs projected forward; all without distinct 
segmentation; tarsus very short, stout, and rounded. Vasiform orifice nearly semi- 
circular (for details and shape see fig. 9, b). 
Pupa case. — White, firm, retaining definite shape, and remains firmly attached to 
leaf unless forcibly detached. (See PL VIII, fig. 1.) 
Fig. 9.— The citrus white fly: a, ventral 
aspect of pupa; b, vasiform orifice of 
same; c, margin of body of same, a, 
Greatly enlarged; b, c, highly magnified. 
(Original.) 
