NOTES

Faunal Speciation in N ew Georgia,

Some 16 years ago the writer made certain contributions to the knowledge of the fauna of San Cristob al, the most eastern of the main Solomon Islands (Lever, Limn. Soc. London, Proc. 148(2) : 82- 83, 1936); this was followed by more general notes on the whole group (Lever, Trop . Agr. [Trinidad] 20(2) : 40-42, 1943) . The purpose of the present paper is to draw attentio n to an extensive local develop­ ment of species formation in the New Geor­ gia group of islands lying in the centre of the whole . FIG. 1. Map of the Gto UP, Solomon Besides the main island of New Georgia, Islands . The outlines of this map have been taken large­ ly from Un ited States Army maps, as the most recent which is some 50 miles in length , the group official British map (No. 17/ 30 of Directorate of Colo­ comprise s seven closely associated islands in­ nial Surveys) shows as a portion of New cluding Kol ombangara which, though only Georgia although in fact a deep-w ater channel occurs 15 miles in diameter, rises to a height of over between the forme r and the intervenin g Woodford Island, with a constrictio n at the Diamond Narrows. 5,500 feet. All these islands, despite their near­ The D.C.G. map marks, but leaves unnamed , the large ness to one another, are separated by very island of ; the spot levels have, however, much deeper water than any other comparable been followed here. The mo st recent edition (1945) of the British Admiralty chart No. 2392 indicates onl y group in (Fig. 1). Thus , although tentative outlines for the coast of western Vella Lavella is only 10 miles from Giza, and adds that Gananggo may be 2 to 4 miles furt her the intervening sea is 245 fathoms deep, and west than its marked position . (Altitude in feet, sea depth in farhorns .) soundings between Rend ovaand Wana Wana, which are onl y 12 miles apart, reached 552 fathoms. small birds take to fly 1.7 kilometers would Recognition of an inter-insular variation in have enabled them to bridge the gap which the animals .of these islands was first noted however, is sufficient to allow of subspecies in the birds by Mayr (Amer. Mus. N ovitates occurring on the different islands. 522: 1 ~22, 1932), who showed that while the That this same phenomenon occurs in in­ thick-head Pachycephala pectoralis is represent­ sects has not heretofore been appreciated. ed by a different species in each of the larger . However, well-marked subspecies of the wee­ Solomon Islands , in New Georgia alone are vil Exophthalmida coerulescens Gunther, taken several species found . Later he showed that by the writer in 1936, were shown to exist by specimens of the white eye, Zosterops rendovae, Marshall (Roy. Ent. Soc. London, Proc., Ser. B. from Vella Lavella and Bagga were distinct 10(4): 51-55, 1941). The typical form, from from those occurring in Ganongga and Giza Vella Lavella, is opalescent grey with many to the south and Kolombangara to the south­ black spots whereas E.'c. ganongae is metallic east (Amer. N at. 74: 249-278, 1940). In fact green, and E. c. kolombangarae is fawn with the flying time of 3.4 minutes which these small dark spots.. A further point of interest

250 NOTES 251

is that, although much more intensive col­ Seitz (Macrolepidoptera ofthe World, vol. 9: 12, leering has been done on the more easterly 1927) as being Kolombangara Island and Ru­ islands of , Isabel, San Cristobal, biana, the latter (also spelled Roviana) being and Malaira, this conspicuous metallic weevil used both for a village on the west of New was never taken on any of them. Georgia and an island lying to the south of This local endemism, which is probably of the main island .] relatively recent origin, is not comparable Although the bulk of the writer's collec­ with the inter-insular variation recorded by tions of anisopterous Odonata were wide­ Marshall (Roy. Ent. Soc. London, T rans. 87(3) : ranging forms, a handsome new species taken 69-101, 1938) for another genus of weevils in 1936, Agriocnemis salamonis Lieftinck (Treu­ (Elytrurus) from Fiji and the New Hebrides or bia 20(2): 319-374, 1949), has recently been various other insects found in the Marquesas described from Ganongga, and it seems likely (M umford and Adamson, V e Congr. Internatl. that adjacent islands will yield more new Ent., Paris: 431-450, 1933), as in these cases material from this neglected order. the islands are separated by varying but ex­ . As few classes of animals have been inten­ tensive distances of open sea. sively collected in this area, it is probable that Among the Lepidoptera one extreme case many interesting varieties remain to be dis­ of aberration of a bird-winged butterfl y can covered although probably not in the Amphi­ be cited, viz., Troides (Ornithoptera) victoriae biaand Reptilia. These were thoroughly col­ rubianus Roths. Among a series from Ganong­ lected and reported on by the Burts (Amer. ga [published as Ranonga], one male had an Mus. N at. Hist., Bul. 63(5): 462- 597). Only unusually large green area on the forewing, one snake (Denisonia woodfordii (Boul.)) is other males showing a less extensive develop­ confined to New Georgia, and it shows no ment (Dicksee, Roy. Ent. Soc. London, Proc, inter-insular variation. 8: 144, 1934). As was remarked when these As the writer is no longer stationed in specimens were exhibited at a meeting of the Melanesia, he has thought it desirable to pre­ Royal Entomological Society, it is strange sent these few observations and thus draw that this Ganongga race should be so very attention to the intensive endemism to be variable as specimens from other islands near­ found in this relatively small but very interest­ by seemed to be constant in wing pattern. ing area.-R. j. A. W. Lever, Department of [The distribution of this butterfly is given in Agriculture, Kuala Lumpur, Malaya.

News Notes

Several meetings of general importance were Council, was held at the Experiment Station held in Honolulu during the week of February of the Sugar Planters' Experiment Station, 16-21. February 18 and 19. 1. J. Dumbleton, Plant The American Institute of Biological and Animal Quarantine Officer of the South Sciences' Advisory Panel on Biology to the Pacific Commission, stationed in Noumea, was Office of Naval Research held its spring meet­ an observer at the meeting. ing at the University of Hawaii February 18 Book Notice and 19. In conjunction with this meeting the EKMAN, SVEN. 1953. Zoogeography of the Sea. Hydrobiology Committee of the AJ .B.S. met xiv-j-dl ? pp., 121 figs. Sidgwick and Jackson at the University on February 20. Limited, London. Distributed in the United The annual meeting of the Invertebrate Con-' States by The Macmillan Company, New sultants Committee for the Pacific, of the York. $6.50. A revised English edition of a Pacific Science Board of the National Research work originally published in German in 1935.