The geographical distribution of animals, with a study of the relations ...

328 ZOOLOGICAL GEOGRAPHY. [part hi.Insects.—The insects of Ceylon also furnish some curiousexamples of its distinctness from Hindostan, and its affinity withMalaya. Among its butterflies we find Papilio jophon, closelyallied to P. antiphus of Malaya. The remarkable genus Hestia, socharacteristic of the Malay archipelago, only occurs elsewhere onthe mountains of Ceylon ; while its Cynthia and Parthcnos areAmongclosely allied to, if not identical with, Malayan species.Coleoptera we have yet more strikiDg examples. The highly characteristicMalayan genus Tricondyla is represented in Ceylon byno less than 10 species ;and among Longicorns we find the generaTetraommatus, Thranius, Cacia, Praonetha, Ropica, and Serixia,allexclusively Malayan or only just entering the Indo-Chinesepeninsula, yet all represented in Ceylon, while not a singlespecies occurs in any part of India or the Himalayas.The Past History of Ceylon and South-India as indicated by itsFauna.—In our account of the Ethiopian region we have alreadyhad occasion to refer to an ancient connection between this subregionand Madagascar, in order to explain the distribution ofthe Lemurine type, and some other curious affinities between thetwo countries. This view is supported by the geology of India,which shows us Ceylon and South India consisting mainly ofgranitic and old metamorphic rocks, while the greater part of thepeninsula, forming our first sub-region, is of tertiary formation,with a few isolated patches of secondary rocks. It is evidenttherefore, that during much of the tertiary period, Ceylon andSouth India were bounded on the north by a considerable extentof sea, and probably formed part of an extensive southern continentor great island. The very numerous and remarkable casesof affinity with Malaya, require however some closer approximationto these islands, which probably occurred at a later period.When, stilllater, the great plains and table-lands of Hindostanwere formed, and a permanent land communication effected withthe rich and highly developed Himalo-Chinese fauna, a rapid immigrationof new types took place, and many of the less specialisedforms of mammalia and birds (particularly those of ancientAmong reptiles and insects theEthiopian type) became extinct.competition was less severe, or the older forms were too well