﻿XXI 



of leaf-hopper, and the burning of trash aggravates the diffi- 

 culty. As an offset to these conditions new fields should l)e 

 supplied artificially with natural enemies, and they should be 

 supplied as soon as any leaf-hoppers enter them. Of course 

 future ol)servation ma_\- ])rove this distribution unnecessary, but 

 for the present it should be adopted. 



LIST OF rARAsrri<:s and their hosts. 



Below are listed the parasites and hyperparasites treated of 

 in detail in the various parts (jf this lUdlctin. In man\- cases it 

 is not ])ossible at ju'esent t(j give the exact host of each ])ara- 

 site. even though the latter was bred. In the first place, of the 

 great number of species of leaf-hoppers collected bv us in Aus- 

 tralia, only about half are yet described, and in the second, 

 many of the ])arasites were obtained onl\- from nym])hs, which, 

 in the i)rcsent state of ]<no\vledge, even the s])ecial student of 

 llomoptera will probably ])e at a loss to refer wilh certainl\- to 

 llieir i)roper s])ecies. The name "Liburnia." often cited l)<.'lo\v 

 as a host, nuist be regarded in a very wide sense, somewhat as 

 in Edwards' "Piritish Homo])tera," where it includes a number of 

 recognized European genera. Ap]died to the Australian forms 

 in the list below, it is likewise a com])osite genus, the com])o- 

 nents of which do not however, at least as a rule, agree with 

 lliose in the work jusl mentioned. In this list of hosts, llie 

 leal-h()))pers have moslK- ])een deternn'ned 1)\- Mr. l\irkald\-. bnl 

 for the reasons given, com|)arativelv few are referred to speci- 

 fically. Conse(|uentl\- it is not necessarv, nor advisable, at pres- 

 ent to make a sec(Mi(l list, gi\ing first place to the hosts, ihongli 

 T hope that this ma\- be done, when the working out of the 

 Homoptera is completed. In the case oi the T^ryinidae 1 have 

 listed all the species dealt with in this Bulletin, since only seven 

 of the 65 have not been bred, and attention is thus called to 

 those species about which information is wanted. 



HYMENOPrJlROUS PARASITES. 



FAM. DRYINIDAE. 



Parasite Host. • 



Pseudogonatopus 



kurandae Eiburnia sj). nym]di and adult, 



juncetorum Liburnia and other Delphacids. nymphs 



uud adults. 



