30 DERIVATION OF THE FLORA OF HAWAII 



The conclusions reached by Meyriclc as to the origin of the Macro- 

 lepidoptera are in remarkable harmony with those of the writer derived 

 from his study of the plants. Meyrick believes the more primitive mem- 

 bers of the lepidopterous fauna have been derived from the Southern 

 Pacific region, and as they are forms of relatively feeble flight it is diffi- 

 cult to account for their presence in the Hawaiian Islands except on the 

 supposition that there was some more or less direct land connection. 

 Meyrick assumes that they reached Hawaii by way of intermediate 

 islands which have now disappeared. 30 



He notes that nearly all the forms of American origin are strong 

 fliers, "and as the trade winds must always have existed, there seems no 

 reason to suspect the previous existence of any intermediate islands be- 

 tween Hawaii and North America." 31 



The case of these strong-flying American insects may be compared 

 with our assumption that the ancestors of the Hawaiian Compositae also 

 reached the islands by means of the northeast trade winds. 



Muir 32 argues that the absence of a number of important groups of 

 insects, especially some of the more primitive ones, indicates that the 

 insects have all reached the islands since their formation ; but as in the 

 case of the absence of certain plants, this may perhaps be explained by 

 assuming the extinction of these missing forms. Or it may be that some 

 of the forms belong to types that have been differentiated at a period sub- 

 sequent to the isolation of the archipelago. 



ARACHNIDA 



According to Simon, 33 there are 101 species of Arachnida, of which 

 seventy-seven are endemic. 



Their relationships are mainly with Australasian and Malaysian re- 

 gions, but there are some Nearctic and Palaearctic types, and an absence 

 of certain tropical types which might be expected to occur. 



MARINE INVERTEBRATES 



Professor W. K. Fisher, of Stanford University, has kindly fur- 

 nished the following statement concerning some of the marine inverte- 

 brates of Hawaii: 



"The faunal position of the marine invertebrates of the Hawaiian 

 Islands may be safely estimated from the relationships of such diverse 

 groups as the hydroids, decapod Crustacea, starfishes and sea-cucumbers. 



a Loc. cit., p. 132. 



31 Loc. cit., p. 133. 



32 Muir, F. : Proc. Haw. Ent. Soc., 3, 198-200. 1916. 



33 "Fauna Hawaiiensis," 2, 443. 



