IN TROD UC TION xlix 



ground beneath forest trees ; the others are, I believe, sluggish, and Hve in very wet 

 moss, clothing tree-trunks in dense wet forests. These are, I suspect, derivations 

 of the genus Campsicnemus, and are undescribed. 



In the Hymenoptera, apterous forms are mostly such as are found in other 

 countries, but the flightless Diapriidae were probably derived from allied fully-winged 

 forms such as still occur with them. In the flightless species intermediate conditions 

 of the abortion of the oro-ans of flieht are known. 



In the endemic Heteropterous bugs, one species of Metrarga has become apterous, 

 and a large section of the genus Redtivioius (Nabidae) is quite flightless, as are the 

 terrestrial members of the family Emesiidae. The species of Acanthia have the 

 wings, so far as is known, always so reduced as to be useless for flight. In the 

 Homopterous bugs many or most of the endemic Delphacidae appear to be always 

 flightless, and if winged forms are produced at all, it must be at very rare intervals. 

 Some, however, are always fully winged, so far as is known. 



The Neuroptera contain the remarkable endemic genera of Hemerobiidae Pseudo- 

 psectra and Nesothauma, both flightless, the former with minute hindwings and the 

 front pair not greatly modified, while the latter has these hardened and sculptured, 

 so as to resemble more nearly the elytra of beetles. These genera appear to be 

 derivatives of the more ordinary Nesomicromus, a dominant genus in the islands. 



In the Orthoptera, the Locustid genus Banza {^Brachynietopa) are all flight- 

 less, while in the Gryllids all the little crickets of the genus Paratrigonidiitm 

 are wingless, and flying individuals are never developed as dimorphic forms, in the 

 way that we have observed in some Trigonididae of other countries. All the 

 prognathous crickets {Prognathogryllus and allies) are flightless, but the wings are 

 so far developed in some forms as to suggest that their present condition has been 

 reached in the islands, while others are without rudiments of wings and almost without 

 tegmina. 



Turning to the Coleoptera, in the Curculionidae, the genera Oodemas, Heter- 

 amphns, etc., containing only wingless forms, are so isolated in structure that one 

 cannot tell whether their winglessness has originated in the islands or whether the 

 forms, from which they were derived, were wingless when they originally reached 

 the islands, but the latter may have been the case, as with Rhyncogvms, the foreign 

 species of which are also wingless. The extensive genus Proterkinns consists of 

 wingless forms, whereas the foreign Aglycyderes is winged. Unfortunately I did not 

 examine the unique example of Samoan Proterhinus, which possibly is a winged 

 form, and the specimen is not at present accessible to me. 



Of the Cioidae many species are flightless and some of these have a remarkable 



superficial form, and have been segregated under a new generic name, Apterocis, but 



other species, still left in the genus Cis, are also flightless, and the wings appear to 



be in different conditions of degeneration, though in most of the species they are 



F. H. I. z 



