PROCEEDINGS OF THIRTY-THIRD FRUIT-GROWERS ' CONVENTION. 151 



black ladybird, Bhizobius ventralis. It increased with wonderful 

 rapidity and the scale was greatly reduced. This species likes a cool, 

 moist climate, and wherever introduced under such conditions, gives 

 good results. 



Great efforts have been made for the discovery of a parasite for the 

 red scale, Chrysomphalus aurantii. This is by far the worst enemy of 

 our citrus industry. Several species of ladybirds have been introduced 

 to prey upon it, and one especially gave promise of becoming a great 

 helper, but I know of few instances where it can be found, and as it did 

 not take hold of the pest as was expected, it can not be counted for 

 much. I refer here to the steel-blue ladybird, Orcus chalybeus. 



Another species which does much good and is a general feeder, 

 attacking the San Jose scale and many other armored scales, is the 

 brown-necked scymnus, Bhizobius lopantha. This species has been in 

 California for a long time and has a good record. It is ever on the hunt 

 for scale insects and does excellent work on the purple scale, Lepido- 

 saphes beckii. I may also mention with the above, Bhizobius debilis, 

 which also is a general feeder, and is generally distributed over the 

 State. Both insects are rather small ladybirds. 



A species which gave great promise in the eradication of the black 

 scale, on account of its good work in its native land, is a steel-blue 

 species, with red spots, Orcus australasiae. Large colonies of this 

 have been liberated in the State, and for a time we could find them 

 in the olive orchards, but I have not seen or heard of any within the 

 last few years and it has probably died out. 



Probably the parasite whose work comes nearest to that of the 

 Vedalia cardinalis is the Scutellista cyanea, the African parasite of 

 the black scale. This parasite in the larval state feeds on the eggs of the 

 scale, which are deposited under it. The small, white, maggot-like 

 larvae can be easily found in any orchard in the coast counties of our 

 State when the scale contains the eggs. Unfortunately, this species 

 does not thrive in the hotter valleys, and this is probably due to the 

 fact that the scale brood is what is called an even brood, that is to say, 

 all scale insects mature at the same time, that egg laying is uniform, and 

 that these conditions leave no food for future generations of the para- 

 site. We also find that in some seasons the work of this parasite is 

 greatly reduced, and from general observations we have found that 

 cold, wet, spring weather, which does not retard the scale, will, on the 

 other hand, do much to retard the breeding of the Scutellista, but 

 where favorable conditions exist, we find its work as near complete as 

 could be hoped for. 



A very small parasite, which is to a certain extent a general feeder, 

 is Aspidiotophagus citrinus, the yellow scale parasite. This is prob- 

 ably an introduced species, but when and how it came to California 



