DERIVATION OF THE FLORA AND FAUNA 315 



So far 49 indigenous genera are cited, of which lO are endemic; five of 

 these are CurcuHonids. 



The non-endemic species are, with one exception — Xyletomerus piibescejis, a 

 N. American species represented by 2 endemic varieties — also found in Chile. 

 As yet no austral-bicentric or -tricentric species have been found. However, 

 Pycnomerodes with 2 species in Juan Fernandez, i in New Zealand and none 

 elsewhere, as well as Pyawmerus, Stroiigylopterus, Eleusis and Enneboeus suggest 

 the existence of a small austral, possibly Antarctic element, even if the area 

 in cases extends north of the Equator. 



Hymenoptera. — The 35 registered species, 5 of them adventitious, cannot 

 represent but a minor portion of the fauna. Just as in all other insect groups 

 endemism is strong, 23 species are endemic [']6.6%] and of the 26 genera 6. The 

 affinities were, as a rule, not indicated by the authors; very likely they are, 

 with some exceptions, with S. American forms. Haplogonatus is essentially south- 

 ern, Prenolepis obscura is a southern, mainly Pacific ant. ApJielms jucu7idus and 

 Stilpnus gagates are said to be boreal, but in these as in other similar cases 

 the possibility of accidental introduction must be considered. 



Hemiptera. — The 21 indigenous species — there are 7 adventitious ones — are 

 by no means a fair representation of the Rhynchota inhabiting the islands. Dr. 

 Kuschel's collection contains twice as many species, more than half of them 

 endemic; of the 21 named species 20 are restricted to Juan Fernandez. Where 

 3 of the 4 endemic genera have their relatives I cannot tell, but the fourth, Micry- 

 menus, is most nearly allied to a genus in New Zealand. Buchaiianiella is quoted for 

 Madeira, Tasmania and Hawaii, but not from America, Nysius, a world-wide 

 genus, has a stronghold in New Zealand and in the Pacific, and the single is- 

 land species stands nearer to a species endemic in New Zealand than to its 

 American congeners. It seems likely that we have to do with an austral- 

 antarctic element. 



Mollusca. 



The following synopsis is based on information supplied by Professor NlLS 

 Odhner who put his unique knowledge of this group at my disposal. The 

 additions and changes in his earlier list (i8g) are entirely due to him, and I 

 thank him for invaluable assistance. Possibly the new material brought back by 

 our 1954-55 survey will give additional taxonomic results, but they will not alter 

 the zoogeographical position of the fauna. 



E7idodontidae . 



-f +A?nphidoxa helicophantoides Pfeifif. — Mt. The genus (only 2 species known) 

 is related to Stephanoda. 



+ A. marmorella Pfeiff. — Mt. 



+ Charopa (Endodonta, s. lat.) involuta Odhner.— Mt. Numerous species, 

 Polyn., N. Guin., Austral., N. Zeal. 



-f C. occulta Odhner. — Mt. 



-f C. skottsbergi Odhner. — Mf. 



