10 
for experimental purposes, living specimens of this extremely valuable 
insect, and we have arranged to accept his kind offer to attempt the 
introduction of the species into California upon a somewhat extensive 
seale. Up to the present time Lecanium olee has not been found else- 
where in this country, except rarely in greenhouses, but it is ex- 
tremely abundant in California, not only upon the Olive but also upon 
Citrus trees. It can hardly be considered one of the most destructive 
of the California scale-insects, but it is a very injurious insect and 
damages trees not only by its own excessive multiplication, but 
by the extraordinary quantity of smut which follows its appearance, 
due undoubtedly to its copious secretion of honey dew. Although 
the Black Seale possesses in California as well as in Hawaii an effica- 
cious parasite in Dilophogaster californica, the latter does not breed 
rapidly and seems to have but two annual generations. Occasionally 
this Chaleidid reaches a point where it destroys from 75 to 90 per 
cent of the Black Scale upon a given tree, but such an occurrence 
is always followed by a rapid restocking with the scales, and the 
benefit is by no means permanent. In Erastria we have a much 
more rapid breeder, and if it should accommodate itself to the some- 
what changed climate, as we anticipate, its introduction will prove a 
boon to the California fruit-grower. In discussing different methods 
of importing the insect, M. Rouzaud has overlooked, as it seems to us, 
the fact that it will be dangerous to bring it over in any condition 
except the egg. Although parasites seem scarce, the known existence 
of one indicates the possibility that at any time an infested larva or 
chrysalis may be brought over and in some degree vitiate the success 
of the experiment. Even at this early date M. Rouzaud deserves the 
gratitude of our fruit-growers for his public-spirited proposition. 
Other things being equal, the Erastria will prove a most profitable 
insect to introduce into California for work against the Black Seale. 
It comes from the native home of the scale insect and is there an 
effective enemy of the species. The Dilophogaster above mentioned 
is not European, and has this disadvantage in addition to that of slow 
breeding. On another page of this number of INSECT LIFE is men- 
tioned, on the authority of Mr. Koebele, the effective work of Rhi- 
zobius ventralis, on the Citrus trees infested with Black Seale in a 
grove belonging to Mr. Elwood Cooper, at Santa Barbara. This is 
one of the lady-birds sent over by Mr. Koebele during the late expe- 
dition to Australia and it has been extensively disseminated. If it 
continues to work as effectively as reported from Santa Barbara, the 
necessity for the introduction of the Erastria may cease, though no 
harm can result from the latter’s introduction, and there are some 
reasons for concluding that it will prove the more effective of the two. 
