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so that even if 1,000,000 winged beetles had been liberated, it would be 

 difficult to find them even a few days later. In all places visited we 

 found evidence of the beetles or larvae and a cleaner condition of the 

 trees. In Mr. Packard's olive orchard the beetles and larvae had spread 

 from the tree where the colony was placed. Here we found larvae of 

 various sizes, from very small to fully developed specimens about ready 

 to change into chrysalis. At Mr. Alfred Wright's olive orchard we found 

 beetles and larvae of Rhizobius ventralis; also a few larvae of Rhizobius 

 debilis. The black scale had done considerable injury to the small inside 

 twigs, but is not so plentiful now. Mr. Loney reported to me that the 

 Rhizobius ventralis larvae were numerous in this orchard about one month 

 previously. It was from this orchard that Mr. Scott sent the parasitized 

 ladybird larvae, that I reported to you on November 9th. After an 

 examination of the orchard, I feel convinced that they are the young of 

 Exochomus, and not ventralis, because the larvae are only found attached 

 to the trunks and under sides of the branches, a position that the latter 

 species, even when very numerous in your orchards, never selected. At 

 this and a subsequent visit to Mr. Wright's orchard I collected the larvae 

 of the Rhizobius ventralis in order to determine if they, too, are subject 

 to the attack of internal parasites, but as yet there is no indication 

 that such is the case. I will raise them until they pass through the 

 larval form. The mature beetle is not subject to the attack of this 

 internal parasite, so I will secure larvae of the Rhizobius ventralis at 

 different seasons in order to fully determine if they are parasitized. 



On December 12th, with Messrs. Collins and Muscott, Horticultural 

 Commissioners of San Bernardino County, I visited the olive orchard 

 of Supervisor I. W. Lord, at Cucamonga, where I placed a colony of 

 nearly 5,000 beetles on September 20th last. This orchard was in a 

 very serious condition when the ladybirds were liberated, nearly every 

 leaf was covered with young black scale, and it appeared to be a very 

 desirable location for a strong colony. During our examination a 

 strong wind prevailed and our search was not very successful, but an 

 inspection of the trees revealed the fact that hardly a scale remained 

 alive. At the time that this colony was placed, another of about 5,000 

 beetles was put in the Dwinelle olive orchard at the head of Euclid 

 Avenue, North Ontario. This orchard was in a more serious condition 

 than Mr. Lord's, but at the present is as free from live scales. 



At Mr. W. C. Farlow's orange grove in North Ontario, where colonies 

 of the Rhizobius ventralis were placed last fall, we could find very little 

 scale. This orchard had also been very badly infested. Mr. Collins 

 believes that the freedom of those orchards from scale must be attributed 

 to heat after the young scales hatched, but it is a fact that we have had 

 no hot days since the ladybirds were liberated. A temperature of 105° 

 to 110° is necessary to kill the larvae of the black scale. As the scale is 

 alive in several orchards at Ontario, Pomona, and Riverside, where the 

 climatic conditions were unquestionably similar, to some other cause 

 than heat is attributable the disappearance of the scale in those 

 orchards. It is claimed that several other orchards are equally free 

 that were formerly infested with scale and where no ladybirds were 

 placed; but the fact that none were put in these orchards does not prove 

 that they did not reach there themselves. In a former report I called 

 attention to the fact that I found the larvae of Rhizobius ventralis at least 

 one mile in a direct line from where a colony was turned out, a low 



