DERIVATION OF THE FLORA OF HAWAII 29 



It is impossible here to discuss all of the orders of insects, and it will 

 suffice to select a familiar order, the Lepidoptera, which has received 

 special attention. Perkins 27 says that of 764 species known to occur in 

 Hawaii, 700 species, or ninety-two per cent, are endemic. 



The Macrolepidoptera have been studied critically by Meyrick, 28 

 who states there are, out of 292 species, 261 (eighty-nine per cent) that 

 are endemic, and that ten genera out of forty-nine are peculiar to the 

 archipelago. Meyrick notes a remarkable degree of resemblance between 

 the Lepidoptera of Hawaii and those of New Zealand, there being no 

 Hawaiian families which are not also represented in New Zealand. 



From his studies on the relationships of the Hawaiian Macrolepidop- 

 tera, and the geographical distribution of the non-endemic species, he 

 concludes that the genera may be grouped under successive periods of 

 time, and that they also indicate the geographical influences of each 

 period. 



To the earliest period belong seven genera, including 133 species. 

 "Probably all of these must be traced to South Pacific origin, and a con- 

 siderable land area (now submerged) between South America and New 

 Zealand is postulated." 29 



Second period Five genera and eighty species, one genus Ameri- 

 can and four Asiatic. "Possibly this period may coincide in time with 

 the considerable extension of the Hawaiian Islands to the northwest 

 which seems to have once existed." 



Third period Eighteen genera and forty-eight species. Of these, 

 six genera are probably of New Zealand or Australian origin, five Asiatic, 

 five American, and two doubtful. This would indicate "a nearly balanced 

 equality of influences with circumstances much as at present." 



Fourth period Twenty-nine species, twenty-one genera. Of 

 these, nine genera are supposed to have been introduced artificially and 

 there are seven cosmopolitan species. Of the remaining eleven species, 

 seven are supposed to be of American origin and four Asiatic. 



"The preponderance of the American element (I think a majority 

 of the cosmopolitan species also came from that side) seems to be ex- 

 plained by the fact that almost all these species possess great powers of 

 flight and find little obstacle in mere distance, but are by no means inde- 

 pendent of the wind; the effect is therefore traceable to the influence of 

 the northeast trade wind." 



27 Loc. cit., p. cxliv. 



28 Meyrick, E. : "Fauna Hawaiiensis," 1, 123-275. 1913. 

 28 Loc. cit., p. 132. 



