134 



found in my published writings, especially in my report as U. S. Ento- 

 mologist for 1891, and it is only necessary to state at this time that 

 parasitized paparia of the Hessian Fly were received in large numbers 

 and distributed to various points, and placed in the care of competent 

 observers in Illinois, Indiana, Michigan, and Canada. The results so 

 far have not been marked, and but one positive report as to the accli- 

 mation of the parasite has been received, viz, from Prof. S. A. Forbes, 

 of Champaign, 111. I am of the opinion, however, that the lack of 

 evidence from other points is due almost entirely to lack of proper exam- 

 ination, and I have every hope that the species will before long be found 

 to have obtained a secure foothold at all of the several points of intro- 

 duction. It is a very difficult matter to ascertain the existence of a 

 parasite of this minute size, except when it occurs in great numbers. 

 It requires an eye trained not only to the examination of these minute 

 creatures, but one familiar with the allied imported species and native 

 species. The reason for attempting the introduction of this particular 

 species was simply that in England it was found to be far more abun- 

 dant and far more beneficial than any of our native species have so far 

 proved. 



The present year I have become interested in the matter of the 

 importation of a predaceous Noctuid (Erastria scitula) which preys upon 

 the Black Scale (Lecanium olece) in south Europe and helps materially 

 to keep it in check. With the help of Prof. H. Kouzaud, of Montpel- 

 lier, France, who has studied the habits of this insect with extreme 

 care, I hope to establish it in southern California, where the climatic 

 conditions are sufficiently close to those of south Europe, and where 

 the Black Scale does great damage to olive orchards and to oleander 

 trees, and also affects less seriously the Orange and Lemon. The Black 

 Scale has already an important enemy in California in the shape of the 

 Dilophogaster above mentioned, but the latter is only two-brooded, and 

 the scale insect, multiplying more rapidly, outstrips it in the race for 

 maturity. The Erastria, on the contrary, passes through five or six gen- 

 erations in the course of a summer, and, as it is purely predaceous, it 

 will, I believe, prove a most useful auxiliary against the Black Scale, 

 especially if brought over without its parasites. 



So far I have spoken only of the insects which have been imported 

 into this country, but some effort has also been made in the opposite 

 direction. Thus we have endeavored (and with some success) to return 

 the service done us by sending to Australia and New Zealand some of 

 our predatory Coleoptera, some of the Pacific coast parasites of the 

 Codling Moth, and a species of the interesting genus Eaphidia, which 

 also preys upon the Codling Moth. 



In 1887 and 1888 the now well-known importation of Vedalia cardi- 

 nalis from Australia and New Zealand to California, to prey upon 

 leery a purchasi, was successfully carried out. The history of this 

 striking example of the beneficial results that may, in exceptional 



