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POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



Head very small, and deeply inserted ; pro-notuni covering a considerable part 

 of the eyes. Eyes coarsely faceted. Antennae, long with club, serrate and 

 three-articled. Maxillary-palpi, securiform. Mandibles, bifid. Prothorax 

 small, with broadly rounded angles. Prosternum flat. Prosternal coxse widely 

 separated, with two converging carinse. Meta-coxal plates entire, very short — 

 shorter than the segment. Epipleurse moderately wide and more or less 

 concave, descending externally, internally margined. Epistoma transversely 

 truncate and simple at apex. Abdomen six-segmented, with sixth segment 

 visible in both sexes. Last segment very small. Claws bifid. 



The adults are scattered throughout the entire county, and may be 

 found at almost any season, without difficulty. As was stated above, the 

 insect was introduced for black scale by Albert Koebele during his second 

 visit to Australia in 1891. It was introduced into the Santa Barbara citrus 



Figure 108. Rhizobius ventralis 



district the same year and in 1893 Mr. Koebele makes the following report 

 concerning it : "On my visit to Santa Barbara during September last year, 

 1 found this insect on the increase, and expected that they would soon be- 

 come numerous. I have been more than pleased, on this last visit, to find 

 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 in the center of the orchard. At that time those trees were 

 all black and covered with Lccaniiim, but they arc now free of scales. The 

 rest of the orchard IkuI been si>rayed last year with kerosene emulsion, but 

 the trees have again become full of Coccids. The beetles arc present in such 



