INTRODUCTION ccix 



in the forests, and sometimes in the open country, one or more species of the parasitic 

 flies of the genus Piptincidus will be found, sometimes numerously. I have bred two 

 species from mixed colonies of Aloha ipomoeae and Nesosydne iponioeicola and another 

 from A^. raillardiae. At Kilauea I observed many of these flies around a Pipturus 

 tree, growing in a shady place, and infested by another N'esosydne, as well as about 

 ferns affected by other species. 



Membracidae. — Represented only by a species of Centrotypiis, of recent introduc- 

 tion. It was first taken in the Nuuanu valley in 1903, since which time it has occurred 

 occasionally and will no doubt become common. 



Tetigoniidae. — This family is represented by a large number of species, closely 

 allied to one another, but forming two genera, one being, so far as is known, peculiar to 

 Kauai, and at present containing few species. Excepting that Nesophryne (the small 

 genus) sometimes occurs on ferns, all the endemic Hawaiian Tetigoniidae (of the exten- 

 sive genus Nesophrosyne) are attached to flowering dicotyledinous plants, and the vast 

 majority of the species frequent the various endemic forest trees. A few kinds only are 

 attached to low growing plants, and one of these, N. perkinsi, is of some interest, as 

 living on a foreign (but naturally immigrant) species of Sida, on or near the coast. 

 The c?i?,& oi N. pei'kinsi SiS regards habits and food-plant and its relation to its forest- 

 frequenting congeners is in several respects similar to that of Aloha ipomoeae in the 

 Asiracid series. 



It is quite certain that a large number of the species oi Nesophrosyne are restricted 

 to a single food-plant, and more than one species may occur on the same individual 

 tree. 



The separation of the species is at present attended with much difficulty, for many 

 of them are very variable in superficial appearance and there is often a considerable 

 difference in the colour or pattern of the sexes. It further seems to be of rather 

 common occurrence, in the case of such species as present these sexual differences, for 

 individuals of the female sex to assume more or less completely the colour of the male, 

 a phenomenon which is also apparent in some of the Asiracid Fulgoroids. In addition 

 to this, a colony of a species infesting one tree sometimes shows considerable differences 

 in appearance, when compared with a colony infesting another tree, even though the 

 distance between the two is small, and these differences are likely to be increased, when 

 colonies from more isolated spots are examined. I have little doubt that any number 

 of superficially distinct forms could be obtained by selective breeding. It is possible 

 that the appearance of individual colonies is often due to the nature of the original 

 parents that colonized the tree, for colonies, if undisturbed, persist on a single tree, as 

 I have experienced, for years. 



Many of the species are certainly common, in fact in some localities, e.g. on the 

 F. H. I. dd 



