ccviii FAUNA HAWAIIENSIS 



larcrest nymphs of some of these flightless species and the same stage of fully winged 

 ones, the tegminal and alar lobes being almost equally developed in each, so that in the 

 species which produce both winged and flightless forms it would appear that the 

 development continues equally in the nymphs of either to the penultimate instar, when 

 in the one case a fully developed wing forms within the wing pad (on which some 

 neuration is visible) while in the other case the wing is reduced to the rudimentary 

 condition of the adult. The nymphs do not appear to be particularly interesting in 

 general, the chief point of interest being the presence of two facial carinae in those 

 which produce adults with only one. 



Kirkaldy tells us that the only Asiracid known outside the islands, having a tibial 

 spur similar to that of the Hawaiian endemic genera, is the arboreal Proterosydne of 

 Australia. 



The genus Dictyophorodelphax, discovered by Mr O. H. Swezey, is remarkable 

 for the great prolongation of the head, a common feature in other groups of Homoptera, 

 but not known previously in Delphacids. It is clearly an offshoot from the more 

 normal Hawaiian forms. 



Many of the species of the native genera exhibit a wide variability of colour, and 

 further frequently the sexes are differently coloured. The males, however, are so 

 easily separated by the great differences in the genitalia, that in the discrimination of 

 the species this is of small moment. Whether there may be different species with 

 similar genitalia is yet unknown, but it is not improbable that such will prove to be the 

 case, when species from all the islands have been more thoroughly collected. The 

 flightless forms are no doubt not easily spread from one locality to another, and I suspect 

 that in many of these a good deal of local variation may be met with. I once examined 

 two large series of Nesosydne pipturi from two different stations in the mountains 

 behind Honolulu, where the species is very common. The first lot were taken from a 

 number of trees, growing near together, in a rather open spot, the second lot from an 

 isolated tree distant not many hundreds of yards from the former. Although possibly 

 individuals might have been picked from each lot agreeing exactly, yet on the whole 

 the two series were so distinct superficially, that until I examined the genitalia I had 

 great doubts whether those from the isolated tree were not a really distinct species. 



The eggs of some of the species are known to be destroyed by Mymarid parasites 

 of the genus Polynenia and nymphs and adults of very many have been found infested 

 by the Strepsipteron, Elenchus melanias. In the mountains of all the islands many 

 species are parasitized by a somewhat aberrant species oi Pseudogonatopus (Dryinidae), 

 this parasite attacking species of Nesosydne, Aloha and probably other genera. 

 On the lowlands Aloha ipomoeae is attacked by Echthrodelphax fairchildii, another 

 Dryinid, which likewise parasitizes the small Kelisia sporobolicola. This leaf-hopper 

 is common on the coasts, feeding on the foreign grass Sporobolus virginicus, and two 

 other species of Kelisia have also been found. Wherever these leaf-hoppers are found 



