21 



Fairchild and I have named it specifically after him. There is 

 no doubt that this parasite has transferred its attack from one or 

 more of the native Delphacid leaf-hoppers to the imported species. 

 I have long suspected the Hawaiian species of Gonatopus to be 

 parasitic on leaf-hoppers and this supposition is greatly strength- 

 ened by the fact that the new and allied form of parasite is so. 

 External parasitic larvae on native leaf-hoppers were found by 

 me many years ago on Hawaii, but I was unable to rediscovei 

 them on my recent hurried trip, the old locality having been 

 spoilt, owing to the total destruction of the forest. Could the 

 Gonatopus be collected in some numbers and transferred to the 

 cane-fields I suspect it would attack the leaf-hopper, as does the 

 parasite now imder consideration. The Gonatopus, being wing- 

 less, has not the same facility for transferring its attack to- the 

 cane leaf-hopper as has the winged Ecthrodelphax. I may add 

 that I believe there is at least one other hymenopterous parasite 

 on the native Dephacids of the forest. 



To return to the Ecthrodelphax, it is always the young of the 

 leaf-hopper that is attacked, and a single hopper may sustain 

 either one or two parasites. These are nearly always lodged be- 

 neath the lobes which develop into the tegmina, or upper wings ; 

 one on each side of the body, when two parasites are present in 

 tlie same host. 



The parasite appears externally as a small, nearly circular, im- 

 pressed black object adherent to the young leaf-hopper. The lat- 

 ter seems to be hardly inconvenienced by the parasite, remaining 

 as active and plump as the non-parasitized individuals. 



After a Lime, however, (always shortly before the full growth 

 of the parasitic larva ) the hopper becomes sluggish and then en- 

 tirely stationary. This may happen either shortly before or not 

 till some time after the black shell-like covering of the parasite 

 splits by a longitudinal (mediodorsal) fissure and exposes the back 

 of the white maggot wathin. This torpidity of the leaf-hopper 

 and the splitting of the covering of the parasite is almo^st certainly 

 the outward sign of a change of habits in the parasite (probably 



