THE CLOUDY- WINGED WHITE FLY: LIFE HISTORY AND HABITS. 91 
its chief limitation is in its lack of important food plants other than 
citrus. Migrations of adults are not an important factor in the spread 
of this white fly except between adjoining groves. Its spread through- 
out a newly infested grove and to adjoining groves is perhaps favored 
by its greater degree of attraction to new growth. It has been 
observed frequently in newly infested groves that it is found to be 
present in very small numbers over a considerable area, whereas the 
citrus white fly, when at a corresponding numerical status, would 
be expected to be more localized. Winds are doubtless concerned 
with the spread of the insect from local centers, but, as with the citrus 
white fly, they are evidently a factor of small consequence in spread 
to distant points. 
Flying insects and birds as carriers of the crawling larvae are neces- 
sarily of little or no consequence in the spread of the cloudy-winged 
white fly, as with the species previously discussed. Between groves 
vehicles of various kinds are of much importance in distributing this 
white fly, as is generally recognized. Without doubt infested citrus 
nursery stock has been the principal factor in the 
spread of the cloudy-winged white fly. Nursery 
stock from Mims, Fla., is quite definitely known 
to have been the source of this white fly at 
Sharpes, Fla. At the present time it seems to 
be the most probable source of this white fly at 
Fort Pierce, Palm Beach, and Miami. 
The species here considered are apparently as 
likely to be carried on the person from an in- fig.i^— The cloudy-winged 
fested grove as is the citrus white fly, the degree ^^ : ^^^ 
of infestation being equal. The same may be 
said of pickers' outfits. The introduction of fungus-infected leaves 
into groves infested only by the citrus white fly in connection with 
the introduction of fungus parasites has doubtless assisted in the 
spread of the cloudy-winged white fly, but not to the same extent 
that this has assisted in the spread of the former species. 
LIFE HISTORY AND HABITS. 
The Egg. 
The egg (fig. 14) of the cloudy- winged white fly differs from that 
of the citrus white fly in that it is not greenish-yellow and highly 
polished, but bluish or grayish black and roughened by a film of wax 
arranged in an hexagonal pattern. To the unaided eye the eggs 
appear as fine particles of blackish dust scattered over the leaves 
(PI. X, fi.g. 1). Because of their dark color they are more readily 
seen on the tender citrus growth by the average observer than are 
the eggs of the citrus white fly. When first deposited they are not 
blackish, but are dull white or cream colored and under the micro- 
