INTRODUCTION ccvii 



the species are widely distributed over the islands, and at present it would be premature 

 to consider that the many, known only from one island, are really confined to one, 

 though no doubt this will prove to be the case in many instances. Nor is it probable 

 that the genus ^Nesodryas, consisting of small insignificant species, is really confined to 

 Oahu. 



As in other parts of the world, these Asiracid leaf-hoppers differ much as to the 

 development of the wings according to the species. Nesodryas in all its species is 

 fully winged. In N^esosydne some species are known, in which fully winged examples 

 occur, but these are much rarer than the flightless individuals. I have certainly 

 examined many thousands of the common N. ipomoeicola in search of parasites, both 

 in the mountains and in the lowlands, where were colonies within a few yards of my 

 house for several years, but fully winged individuals were rarely met with. For several 

 consecutive days I examined for the same purpose great numbers of N. raillardiae, 

 but I never found any but flightless forms. Still they may be produced at irregular 

 intervals. Nesosydne koae and some others are only known as fully winged individuals, 

 though the species named occurs in profusion. 



In the genus Aloha the conditions are very similar to those in Nesosydne. In 

 A. ipomoeae fully winged forms are rare as in Nesosydne ipomoeicola, though this species 

 also has been examined in equal numbers for parasites. A. lehuae and its allies are 

 always fully winged, but of Nesopleias nimbata it is unlikely that winged forms are ever 

 produced, since the very short tegmina have become thickened and the neuration more 

 reduced than in brachypterous A. ipomoeae. It would appear probable that in the 

 various endemic genera, species, which we know from a fair number of examples of 

 fully winged individuals, are not likely to yield brachypterous ones under any circum- 

 stances, while the normally brachypterous species sometimes produce fully winged 

 individuals in small numbers, but more often are entirely brachypterous. We know no 

 Hawaiian Asiracid, in which both winged and flightless forms are more or less equally 

 common, no such case in fact as is presented by the two introduced forms Perkinsiella 

 saccharicida and Peregrinus maidis. In the former of these winged examples are 

 always common, and flightless females abound in the colder months of the year. In 

 the latter both forms in both sexes abound at various seasons. Nesorestias contains a 

 single species with very short tegmina, and is not likely to yield a winged form, the 

 peculiar structure and texture of the tegmina being analogous with that of flightless 

 Hawaiian Hemerobiids in the Neuroptera. 



In the Hawaiian Asiracids it should be observed that, whether fully winged or 

 flightless, both sexes agree in this. No species are known, which, like the introduced 

 Perkinsiel/a, produce brachypterous individuals in one sex only. In the flightless 

 Hawaiian forms the wings are reduced to microscopic rudiments, but can be seen in all 

 the species that I have examined. There appears to be little difference between the 

 ' More than one species of this genus is now known from Kauai. 



