20 



grown, and they left their hosts and spun cocoons in a few 

 days. These were undoubtedly attacked by the Ceraphronids, 

 for Vvathin 3 weeks from the time the experiment was started, 



I (..^eraphronid emerged from a cocoon, and in a few more days 



II more emerged. 



At the same time another experiment was conducted. A 

 number of leaf-hoppers already parasitized by Haplogonatopus 

 were collected from the field and placed in two breeding cages. 

 In due time the parasites spun their cocoons. Then adult 

 Ceraphronids were admitted to one cage, but not to the other. 

 From the latter cage adult Haplogonutopus emerged from all 

 of the cocoons; while Ceraphronids emerged from all of the 

 cocoons of the former cage. This proves that the Ceraphronid 

 attacks its host only after it has made its cocoon. 



Along with Haplogonatopus vitiensis there were a few Ech- 

 throdelphax faircliUdii also breeding upon the cane leaf-hop- 

 pers. To ascertain whether this Ceraphronid was breeding up- 

 on this Dryinid also a number of leaf-hoppers already parasit- 

 ized by it ^vere collected and placed in a breeding cage until 

 the parasites had left the leaf-hoppers and spun cocoons. 

 Ceraphronids were then admitted. In about three weeks Cerap- 

 hronids issued (the first one in 19 days), and it was found that 

 they had parasitized all of the Echthrodelphax cocoons. The 

 adult Ceraphronids issuing from these cocoons were smaller 

 than those issuing from Haplogonatopus cocoons; the larva of 

 Echthrodelphax being smaller than that of Haplogonatopus 

 accounts for the difference in size of the parasites issuing from 

 them respectively. 



So far as previous records show Ceraphronids have been 

 bred from Lepidoptera, Aphids, Syrphids, Cecidomyids, 

 Cynipids, Braconids, ants and some Coleoptera. Chiefly, how- 

 ever from Aphids, Cynipids and Cecidomyid galls ; but now 

 we have the remarkable case of a species breeding upon members 

 of the closely related family, Dryinidae. Of these two Dry- 

 inids in questions, Echthrodelphax fairchildU is a native species 

 preying upon the sugar cane leaf-hopper (Perkinsiella sac- 

 charicida) and certain native leaf-hoppers of the same family 

 (Asiracidae). The other Dryinid {Haplogonatopus vitiensis) 

 was introduced from Fiji, in 1906, to prey upon the cane leaf- 

 hopper. 



