

GENERAL REMARKS ON PARASITES OF LEAF- 

 HOPPERS. 



In Bulletin I of the Division of Entomology an extensive 

 account of leaf-hoppers and their natural enemies was prepared 

 by the members of the staff, and in Bulletin II some additional 

 observations were recorded by Mr. F. Muir, who visited Fiji, 

 for the purpose of investigating leaf-hoppers and other insects 

 in that group. In the present Bulletin a large number of parasites 

 observed and collected by Mr. Koebele, chiefly in Arizona, are 

 recorded, as well as such of their hosts as can be at present deter- 

 mined. A considerable amount of material, consisting of leaf- 

 hoppers themselves, left over from Mr. Koebele's and my own 

 expedition to Australia and from Mr. Muir's to Fiji has also been 

 worked out and is ready for publication. In addition to these 

 collections my work on the parasites of leaf-hoppers has been 

 greatly aided by other specimens received from Mr. Koebele. 

 In the summer of 1905 he visited Germany on a vacation trip, 

 and during this vacation was so good as to collect for me a con- 

 siderable amount of European material. These European speci- 

 mens have been of the greatest service in working out the Ameri- 

 can species, and enable me to correct a number of errors in my 

 former papers on the Dryinidae. Mr. Koebele not only sent over 

 specimens of these and other parasites bred or captured by him- 

 self, but also a number of cocoons and puparia, that he had ob- 

 tained there. It was very satisfactory to breed here, in these 

 islands, species of European Gonatopus, Chelogynus, Anteon 

 and others of the Dryinidae, as well as species of Piptmculus with 

 Verrallia aucta and villosa of the Diptera, and to be able to 

 examine all these alive. In addition to Mr. Koebele's consign- 

 ments I have also examined some material recently received from 

 China, collected by Mr. Muir. It will therefore be seen that the 

 work done on the subject of leaf-hoppers, and their enemies, 

 both in the field and study, has been of a very extensive character 

 and it is possible to come to some general conclusions, as to what 

 enemies keep the countless species of leaf-hoppers— all of which 

 are potentially injurious— in check, throughout a large part of 

 the world. One is at once struck with the fact, that whether in 

 Europe, Asia, Australia or America, the parasites or predators 



