THE CITRUS WHITE FLY: LIFE HISTORY AND HABITS. 51 
might readily produce a sufficient number of adults to successfully 
establish the pest. Such leaves, after introduction, would need to 
have a favored location, for exposure to much sunlight or to too 
much moisture would soon destroy the insects. 
Introduction on leaves infected with parasitic fungi. — The matter of 
spread of the white fly in connection with the attempt to introduce 
parasitic fungi is a subject of considerable importance. The danger 
here is due to the failure to recognize the distinction between the 
citrus white fly (Aleyrodes citri) and the cloudy-winged white fly 
(Aleyrodes nubifera). The owner of a grove infested by the latter 
species only, would provide a very favorable opportunity for the 
introduction of the first and most destructive species if in introduc- 
ing parasitic fungi he should obtain his supply of leaves from certain 
sections of Florida. The spread of the cloudy-winged white fly has 
been encouraged in a similar manner. The tree-planting method of 
introducing the fungi, especially the brown fungus, is the most dan- 
gerous practice in this connection. Of somewhat less danger in the 
individual cases, but of far greater danger on account of the more 
frequent opportunities presented, is the introduction of fungus- 
infected leaves for pinning or for spraying the spores. The pinning 
of leaves as a means of introducing the parasitic fungi has little more 
to recommend it than the tree-planting method, but it has without 
doubt been the means of introducing the citrus white fly on many 
occasions. Leaves introduced for the spore-spraying method of 
spreading the fungus parasites are an element of much danger under 
certain conditions. Some sections of Florida in which only the cloudy- 
winged white fly occurs are in more danger of having the citrus white 
fly introduced by some uninformed person in this way than they are 
of its introduction in any other manner. Specific examples might be 
cited where the introduction of either A. citri or A. nubifera was 
with little doubt due to introducing fungus-infected leaves or trees, 
but the danger is too obvious to require further discussion in this place. 
LIFE HISTORY AND HABITS. 
Summary. 
The eggs of the citrus white fly (fig. 3) are laid scatteringly, with 
few exceptions, on the underside of the leaves of the various food 
plants, and hatch in from 8 to 24 days, according to the season. 
During ordinary summer weather from 75 to 100 per cent hatch 
on the tenth to twelfth day. Infertile eggs hatch as readily as fertile 
eggs and produce adults of the male sex only. After hatching, the 
young larva (figs. 4-6) actively crawls about for several hours, when 
it ceases to crawl, settles upon the underside of the leaf, and begins 
to feed by sucking the plant juices. It molts three times before 
