75 



success, large or small, has been attained in a number of cases is 

 without doubt. The classic case is of course the effect produced 

 by iVorius (Vedalia) cardinalis Muls. against the cottony cushion 

 scale {Icerya purchasi Mask.) in California. I have followed in a 

 very general way the records of the successes attained in foreign 

 countries, including under that term, for convenience, Hawaii. There 

 is no doubt that not only a measure of success has been obtained in 

 many instances, but that the measure has been in a few cases a very 

 satisfactory one, amounting in the California instance just cited to 

 the almost complete extermination of the pestiferous insect. 



At first blush there seems to be no reason why what has been done 

 in one section of the country can not be equally well done in another; 

 and why. if it has been shown that on the Pacific coast a species of 

 coccinellid is found keeping a scale insect in check, that same species 

 should not do precisely the same w-ork in the vState of New Jersey. 



With this idea, I made my first visit to California and the Pacific 

 coast in 18DG; in the first place to determine whether, as against the 

 San Jose scale, the coccinellids were really effective, and, second, 

 whether it would be possible to acclimate these insects in New Jersey. 

 A few years ago I would have said that what can be done in Cali- 

 fornia can also be done in New Jersey, and that the results of experi- 

 ments obtained in New Jersey were equally valid in California. The 

 experience of the past few years has modified my opinion on this 

 subject ver}'- materially. I am extremely reluctant nowadays to even 

 advise a New York or a Pennsylvania fruit grower to make applica- 

 tions based upon what I have found to be effective in New Jersey. 

 In fact, I have discovered that I can not always duplicate rasults two 

 years in succession ; that Avhen I find an application almost completely 

 effective one summer, I am as likely to find it, under apparently 

 similar conditions, absolutely ineffective the year following. Perhaps 

 it does not often occur that such extreme contradictions are noted; 

 but I think every Avorking economic entomologist has seen cases at 

 least similar to the one just suggested. 



I do not encourage too great hopes from importations made from 

 California into New Jersey. You are probably familiar with the 

 report made by me in 1897 as to the results of my investigation ; how 

 I found that in the more southern parts of the State the pernicious 

 scale was really kept in check by a coccinellid not the species which 

 liad been credited with the work, but b}^ a common native form, 

 ChUocoriis hiruliienis Muls. I found, too, that the species that was 

 most generally credited with being the check to the scale could 

 scarcely be found at any time, and that instead of Rliisohius lophantce 

 Blaisd., which is an introduced species. Scymnus inapginicollls Mann. 

 is really the eftectiAe form. Nevertheless I succeeded in making ar- 

 rangements by which I introduced into the State of New Jersey dur- 



