532 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 84 



The Californians for some years carried on spectacular work with 

 Coccinellids collected by the hundreds of thousands during their rest- 

 ing period in the mountains and that were carried down into the 

 valleys of the southern part of the State to destroy plant-lice in the 

 large melon fields. S. J. Hunter in Kansas tried once to breed up 

 aphid parasites to control the grain aphis when it supposedly invaded 

 Kansas wheat fields from the South. And F. M. Webster, while 

 working for the United States Bureau of Entomology, had parasitized 

 puparia of the Hessian fly collected in Pennsylvania and exposed in 

 infested fields in Maryland with encouraging results. The parasite 

 (Polygnoius hieinalis) apparently established itself immediately to 

 good effect in the Maryland field. Under W. D. Hunter, parasitized 

 boll weevils were carried successfully from Waco, Texas, to Dallas, 

 Texas, and from Texas into Louisiana, with the result that the mor- 

 tality of the weevil was increased in both localities to which the para- 

 sites had been taken. 



It is surprising that more of this work was not done at an earlier 

 date. The writer well remembers that in 1896, when practically all 

 the shade trees in the District of Columbia were damaged by larvae 

 of the white-marked tussock moth, there developed an enormous 

 number of parasites in the northwest quarter of the city which in the 

 other sections were scarce or entirely lacking. It would have been 

 easy to supply the suffering sections with an abundance of parasites 

 from the northwest section. The emergency passed, however, without 

 action of this kind, and, although the damage to the trees lasted a 

 season longer in the quarters lacking parasites, other factors com- 

 bined to lessen the injury during the following years. At all events, 

 the damage ceased. 



The men in the tropical research laboratories in Cuba have noticed 

 that the sugar cane borer is sometimes held down to some extent by 

 its parasites in certain restricted regions while miles away parasites 

 are lacking. Transfers in bulk of parasites are plainly indicated. 



As I am writing this Dr. W. Dwight Pierce, who has been employed 

 for a year or more by two of the great sugar companies on the Island 

 of Negros, has visited Washington. He has told me some very inter- 

 esting facts about the transfer of i)arasites in the sugar cane fields 

 from particular {xjints where they abound to other points in the same 

 general area. He has in this way a number of times increased very 

 greatly the percentage of parasitism of the prevalent sugar cane borers. 

 His reports when published will undoubtedly be of great interest. 



Another rather extraordinary exam|)le of successful transfer of 

 indigenous parasites is apparently just being brought about at Halsey, 



