74 
before 4 p. m. in sunshine were invariably somewhat injured, some of 
the younger limbs dying back and all the leaves usually shedding. 
The fallen leaves were all replaced by new growth in a few weeks and 
no permanent injury was done, but the crop upon such trees was notice- 
ably reduced. The dropping of leaves from a tree in Florida has 
comparatively little significance, the trees instead of dying, as they 
sometimes do in California, putting on new foliage-and going along as 
if nothing special had happened. However, the burning of limbs and 
injury to bloom is another matter, and therefore midday fumigation 
can hardly be practiced. While some defoliation occurred with trees 
fumigated at other times than midday, even after night, it was not 
strikingly noticeable nor was damage to limbs or crop of sufficient 
amount to be detected after a few months. Some of this work was 
done as late as February 18, when the blossoms were beginning to open, 
some of them being well expanded. The bloom seemed unaffected by 
the treatment unless the work was done with the sun at high meridian. 
The white fly seemed practically exterminated upon the treated 
trees. In examining hundreds of leaves from dozens of trees about 
ten days after they were fumigated, and covering thousands of insects, 
I was able to find but a single living specimen. If a grove was segre- 
gated from all others, I have no doubt that one fumigation would 
render it so nearly clean that it would need no additional attention 
for two or three years. The great hindrance to its becoming a prac- 
ticable remedy is that few groves are so isolated that the fly will not 
come to them from neighboring groves, and since the insect seeks 
young and tender growth for egg-laying purposes there is, perhaps, 
some tendency for it to go to trees that have been fumigated and are 
therefore putting out new growth. Under ordinary circumstances 
the insect is not a great traveler, though winged, and will often take 
a whole season, extending over three full broods, to spread over a 
10-acre grove. Its progress will be marked by the trees showing 
sooty mold. 
Special observations were made to determine the effect of the gas 
upon ladybugs. On the afternoon of January 22, 72 ladybugs, almost 
all Chilocorus bivulnerus, which had fallen to the ground under fumi- 
gation treatment, were placed in a shallow tin box and left until 
January 23; at 9.30 a. m. of the latter date 70 beetles were in the 
box, a few of them active; at 4 p. m. 66 remained in the box, about a 
dozen of them showing signs of activity. At 8.45 a. m. January 24 
62 ladybugs were in the box, and 60 at 12.40 p.m. The 60 never 
exhibited signs of animation, all being observed to be dead several 
days afterwards. January 24, by | p.m., another lot of 176 fallen bugs, 
nearly all of the same species as before, was collected and kept in the 
same manner as the first ones. January 25, at 4.30 p. m., 160 of these 
were dead, 16 out of the lot having recovered. In the first lot 16 per 
cent of the whole revived; in the second lot about 9 per cent. 
