13 
MODE OF SPREAD AND DISTRIBUTION. 
All young scale-insects are quite active when they first hatch, and 
most of them at this time are extremely small, and when very thick 
upon a tree, instinctively, or at least very easily, drop from the terminal 
twigs and branches. Their specific gravity at this time is so light that 
they are easily wafted with the wind in their descent. This general 
truth applies with equal force to the Icerya, which is readily carried 
from tree to tree and from orchard to orchard by the agency of wind, 
by running water, or by birds or other insects. Another local means 
of transport not to be ignored, is upon the clothing of persons engaged 
in cultivating, upon packages, and upon all implements used, whether 
in cultivating or harvesting the crop. This particular spectes also has 
quite a habit of crawling over the ground, and its local spread is very 
materially enhanced thereby. 
It is carried long distances, however, chiefly by high winds, birds, 
and commerce, and its introduction from one continent to another has 
undoubtedly been effected by the latter method upon young trees or 
cuttings. 
NATURAL ENEMIES. 
No bird is known yet to attack this iusect in California, and but one 
is mentioned even in Australia, and that upon very slight evidence Of 
predaceous insects, a species of Lace- wing (genus Chrysopa) has been 
observed to feed upon it, as also the Ambiguous Lady-bird ( Hippodamia, 
ambigua). The larva of a little moth, which I have described as Blas- 
tobasis iceryceella , is also known to feed upon the eggs. Among the 
Heteroptera, or true bugs, quite a number have been found upon the 
trees infested with the insect, but none have yet been noticed to feed 
upon it. The most important of its insect enemies are a species of ear- 
wig not yet identified, and a number of mites not yet carefully studied. 
Of true parasites, none have hitherto been reported, whether in Aus- 
tralia, Africa, or America, but I am glad to announce that two speci- 
mens of a minute Chalcid-fly have been bred by me from specimens 
around Los Angeles, and will be described by my assistant, Mr. L. O. 
Howard, who makes a specialty of the family, under the name of Isodro- 
mus iceryce. The genus is new to our fauna, and the probability is that 
this little friend was introduced from Australia with its host.* 
PREVENTIVE MEASURES. 
Most of the members of this society are doubtless aware that for 
some four years I was conducting a series of very careful experiments 
with a view of controlling the scale-insects and other insect pests that 
injuriously affect the orange trees in Florida. This work was carried 
*Mr. D. W. Coquillett informs me that he lias since reared a Proctrotrupid, proba- 
bly of the genus Cosmocoma, from the male pupa. 
