28 
that the beetles can now be found by the millions. The first orchard 
visited was the one in which the first beetles received by Mr. Cooper 
were liberated upon 49 trees reserved in the center of the orchard. At 
that time those trees were all black and covered with Lecanium, but 
now they are free of scales. The rest of the orchard had been sprayed 
last year with kerosene emulsion, but the trees have again become full 
of Coccids. The beetles are present in such numbers, however, that it 
will be but a few weeks until the whole orchard will be clean. The 
upper orchard, where beetles were liberated at the end of May of last 
year, is practically free of scales,and from here the Rhizobius have 
spread to the central orchard and can be found by the hundreds upon 
every tree. The beetles were seen in copulation everywhere, and on 
nearly every branch the females were seen thrusting their eggs under 
the old scales. It will be but a very short time until every tree is clean 
of scales, and no time should be lost in collecting and distributing this 
valuable insect to all parts of the State. Mr. Cooper informs me that he 
has already sent out several colonies and I took occasion to visit a prune 
orchard near San José infested with L. olew, where a colony of these 
beetles was placed on July 31. The mature beetles were still present, 
and their larve, up to about half grown, quite numerous. This, in 
fact, is the second colony set out, the first being liberated on June 29, 
and beetles could still be seen when the second lot received from Mr. 
Cooper were liberated. I have not seen the first colony, but have not 
the slightest doubt that this also is on the increase. This beetle isone 
of the most common Coccinellids in Australia, preying chiefly upon 
Eriococcus, Rhizococcus, and various Lecaniine, and upon these last it 
could always be found in New South Wales on my last trip. On my 
first trip I forwarded this insect to Los Angeles from South Australia 
and Victoria, where it was erroneously supposed to feed upon Icerya. 
Within two years at the longest I believe that the various Lecanii in 
California (and Florida as well) will have succumbed to the ferocity of 
this little beetle. 
Rhizobius debilis Blackb. 
A year ago this beetle could be found nearly as numerously as the 
foregoing at Mr. Cooper’s ranch, but at the present time they are by no 
means so abundant. R. ventralis has increased so rapidly that this 
species, in effect, is lost among the vastly greater numbers of the other 
species, and there seems little likelihood of this species maintaining 
itself at this place. It is this species that keeps the olive trees practi- 
cally free from black scales (Lecaniwm cassinie) around Adelaide, South 
Australia, and I have always found the two species working in har- 
mony upon Lecanium in New South Wales. The enormous increase of 
the one species and the decrease of the other here is no proof that the 
latter insect is of less value, and if R. debilis had outnumbered R. ven- 
tralis at the beginning we should probably now see things reversed. 
