INVERTEBRATES 283 



adjacent mainland, but at the same time exhibit distinct evidence of long isolation 

 by the fact that out of thirty-six land-snails no less than fifteen are peculiar. 

 About the same proportion of restricted forms characterises the land-snails of the 

 Solomon Islands, fifty out of one hundred and fifty coming under this category. 

 The great feature of these islands is the extraordinary number of species of 

 Papuina, some of which display remarkable eccentricities of form. In habits 

 these snails are mainly arboreal, and they may be met with in profusion on the 

 branches and leaves of trees both in New Guinea and the Solomon Islands. 



Among the host of Papuan insects it must suffice to refer to the abundance of 

 the gorgeously coloured butterflies belonging to Ornithoptera and certain allied 

 genera, notable not only on account of their large size, but also from the great 

 difference between the males and females of the same species. Ornithoptera 

 itself, as now restricted, is largely a Malay type, although some of its members 

 inhabit the Moluccas and the typical Papuan islands, but the species of Troides 

 are mainly found in the Papuan area, to which the handsome T. priamus and 

 its existing relatives are almost restricted, that particular kind being a native of 

 Amboyna and Ceram. The allied genus A^tlieopteris is typified by JE. victories 

 of the Solomon Islands, in which the females are considerably larger than their 

 partners; the same being the case with the striking species, Schoenbergia 

 paradisea from the Finisterre Mountains of New Guinea, shown in the annexed 

 illustration, which is the sole representative of its genus, and lives at an elevation 

 of about 1500 feet above sea-level. The males, which measure five inches across 

 the wings, have the front pair of wings black, marked by two broad green bands 

 glossed with golden yellow, and a shorter bar of the same colour on the hind 

 margin. The hind-wings are green, more distinctly tinged with golden yellow 

 than the front pair, and narrowly bordered on their outer margins with black, 

 and with a broader band of the same at their bases and on the inner margins. The 

 females, which are considerably larger, are black with a double row of white 

 spots on the front-wings, these decreasing in size and converging as they approach 

 the hind-angle. The second pair of wings display a pale band near the free 

 margin, while the outer portion is yellow, shading into bluish grey and whitish, 

 and traversed by a row of black spots. These splendid butterflies, which belong 

 to the swallow-tail family (Papilionidce or Equitidce), are in the habit of hovering 

 round and about the perfumed white flower of Cerbera odollam, a plant related 

 to the oleander. Their caterpillars carry strong spines, and the strange form 

 of the pupa suggests that it developed for the purpose of terrifying birds and 

 other enemies. 



As regards crustaceans, it is probable that the Papuan province possesses 

 crayfish akin to those of Australia. As a common inhabitant of the islands of 

 the province, to which, however, it is in no wise restricted, reference may be 

 conveniently made in this place to the great cocoa-nut crab (Birgus latro), which 

 in general appearance recalls a monster hermit-crab. These crabs subsist chiefty 

 on cocoa-nuts, to procure which they often climb the palms, if they cannot find 

 fallen nuts. Although doubts have been expressed in regard to the truth of this 

 statement, it has been found to be authentic by observations on captive speci- 

 mens at Batavia and examples near Bantam which have been actually seen 



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