346 C. SKOTTSBERG 



are unfit for long journeys; whether they are transported by waves and currents and 

 able to stand immersion in salt water during weeks and months I do not know. 

 The endemic Sightless insects have, just as the flightless birds, given cause to 

 much s[)eculati()n. They are supposed to descend from winged species; arrived, it 

 is said, on an oceanic island, they had the choice of losing their wings or being 

 blown oft' the island and lost altogether. ZIMMERMAN does not favour this view, 

 for they may as well have lost their power of flight on the mother continent, 

 which did not prevent them to be carried off by a hurricane. Mayr agrees with 

 him, comp. quotation p. 336. Very well, but is it possible to imagine a flightless 

 rail carried a thousand miles across an ocean.' 



There are numerous Ortlioptcra on Hawaii, most of them endemic species or 

 even belonging to endemic genera. So far only 4 species have been reported from 

 Juan Fernandez, two of them endemic. I presume that Zimmerman regards these 

 insects as normally wind-borne. The relations of the Hawaiian Gryllidae are with 

 Indo Pacific forms, so they have had a long way to go. The four species of 

 tciDiitcs found in Hawaii are adventitious, which should indicate that they are 

 unable to reach oceanic islands without human assistance, but the single species 

 discovered in Juan Fernandez (Masatierra) is endemic. Either did it, or its ancestor, 

 arrive over land, or a colony was carried in a floating log, which may seem un- 

 likely, or a storm brought a winged, swarming couple which founded a new colony 

 — even less probable. The termites are a very ancient order and date, it is said, 

 back to the Mesozoic at least. 



Mallophaga are spread with their bird hosts. All the endemic Hawaiian species 

 live on the Drepanididae, and the marine birds here and on Juan Fernandez are 

 infested with widespread forms. Tliysanoptera seem to be easily' spread with human 

 traffic. Most of the 90 species found in Hawaii are adventitious, few indigenous. 

 Two of the 4 species in Juan h'ernandez are endemic. How these delicate insects 

 manage to get about and to reach oceanic islands I cannot tell. 



Tlie Hawaiian islands have a rich and peculiar fauna of Xcuroptera, some 

 "among the most aberrant of all" (ZIMMERMAN p. "j6). Of the five species re- 

 corded for Juan Fernandez 4 are endemic, one of them belonging to an endemic 

 genus. Wind drift must be taken into account, but it cannot be very effective. The 

 situation remains tlie same when we get to the Lepidoptera, about lOOO species 

 in Hawaii, of which 85 % have not been found elsewhere. Wind drift or immature 

 stages (eggs, etc.) carried with plant material are the only possibilities, but they 

 cannot be very great. vSo far only 26 indigenous species are known from Juan 

 I^'ernandez, 70% of them endemic; when the list of Dr. Kusciiel's collection, which 

 contains over 50 species, has been published, the figures will undergo alteration. 

 In his survey of the Pacific lepidoptera Swezev [262) includes the Galapagos 

 Islands, but does not mention Juan Fernandez. The Pacific islands were, he says 

 p. 319, j)opulated from the Malayan and Oriental regions, and the fauna arrived 

 in the main by accident, winds, ty[)hoons etc, or with plant material brought by 

 currents. A comparable numerical development of species per genus has taken 

 place in no other islands than the Hawaiian, and the author infers that they have 

 a more ancient fauna, descended from ancestors that arrived at a more remote 



