98 WHITE FLIES INJURIOUS TO CITRUS IN FLORIDA. 
be presented illustrating the disastrous effect on the species resulting 
from overcrowding, the data itself would differ in no respect from 
that already presented under the general consideration of A. citri. 
Nevertheless, there is a great difference in the extent and practical 
bearing of this mortality among the immature forms of the two 
species. 
The Adult. 
The adult of the cloudy- winged white fly is similar to that of the 
citrus white fly, but is at once separated from it by the dark spot 
or shading on the outer portion of the upper wings (PI. X, fig. 1). 
Except for the further fact that the female is appreciably more robust 
the adults of both species are structurally much alike. The antennae 
of A. nubifera are not as highly corrugated as those of A. citri, but 
possess a terminal spine over three times as long as that of A. citri. 
The eyes of A. nubifera are more nearly divided in many instances 
than those of A. citri, although this is a character subject to variation 
in both species. 
On nearly all features of lif e history and habits this species closely 
resembles the citrus white fly, and these subjects are therefore dealt 
with in a comparatively brief manner. The principal points wherein 
the cloudy-winged white fly differs from the citrus white fly may 
be stated summarily as follows : It is more closely restricted to citrus 
for its food supply as well as in oviposition; it shows a more strongly 
developed tendency to feed and deposit eggs on new growth; its 
arrangement of eggs and preferences for certain sections of leaves 
for ovipositing are characteristic, and it is slightly less prolific. Its 
apparent restriction to citrus as a food plant has been discussed under 
the subject of "Food plants.'' Its strong preference for new growth 
results in a situation which can be taken advantage of in the con- 
trol of the pest by the pruning of water shoots. 
The age at which oviposition begins and the activity in oviposition 
during different parts of the day are the same as for A. citri. The 
females, however, when not abundant deposit more readily along the 
outer margin of the under surface of the leaf and along the edge 
and upper surface, and not so freely along the midrib as is the case 
with A. citri. Not infrequently 90 per cent of the eggs will be 
deposited on the outer portion of the leaf while many are laid on the 
edge of the leaf itself, from winch they often project perpendicularly. 
The depositing of eggs on the leaf margin and on the upper surface 
is peculiar to A. nubifera and is not the result of overcrowding. A 
count of 4,000 eggs on nine moderately infested leaves showed that 
8.1 per cent of the eggs were laid on the edge of the leaf, 86.8 per cent 
on the lower surface, and 5.1 per cent on the upper surface. When 
adults are very numerous both surfaces of the leaves of tender 
growth and the petioles and shoot stems are thickly covered with 
