136 
even although it may ultimately be proved that they are 
scarcer relatively than the beetles. 
Dr. Sharp* divides the coleopterous fauna of the Islands 
into three divisions : first species (chiefiy cosmopolitan) 
introduced in stores, ballast, &c., by commerce; second 
species introduced by natural currents in drift-wood, &c. ; 
and third endemic or autochthonous species, the latter being 
distinguished from the second by structural peculiarities, 
being to all appearance forms of great antiquity, the dis- 
tinction between the two groups being owing, no doubt, to 
the fact that the autochthonous species were introduced 
into the islands at a much more remote period — so remote 
indeed that their nearest allies have become extinct or 
nearly so on continents, where the struggle for existence 
has been much keener. 
My knowledge of the Rymenoptera is not sufficient to 
enable me to separate the species which belong to Dr. 
Sharp’s two last categories ; yet I have no doubt at all that 
most of the species of Crahro, Odynerus and Frosopis have 
originated in the islands by evolution from one or two 
species introduced at some remote period into the islands by 
currents on drift-wood. The aculeate species found in the 
Archipelago belong to genera which we might d priori 
expect to find there, being species which form their nests in 
or on wood, the genera which nidificate in the ground being 
absent. 
The following species have, I believe, been introduced by 
Man’s Agency :—Gamponotus sexguttatus, Ponera con- 
trocta, Monomorium specularis, Tetramorium guineense, 
Frenolepis longicornis, Fheidole megacephcda, Solenopsis 
geminata, all ants of wide range. Pelopaeus caementarius, 
Folistes aurifer^ P. hehraeus, Xylocopa ceneipennis, Evania 
laevigata, Metacoelus femoralis, and Spalangm Jiirta. 
It is possible that P. hehrwus may belong to Sharp’s 
*Scient. Trans* of the Eoy. Dub. Soc., III., p. 269. 
