201 



The Alohac eonsists of several iiroups of verv distinct in- 

 sects; even the lienns Ncsosydiie contains i>Ton])s of diverse 

 species. This wonld indicate a verv ancient ininii,«>'ration. 

 Another ])oint of interest is that a niajoi'ity of tiiese species 

 arc brachvpterons. 



ThcLeialohac consists of two o-pnera, se])arated by the 

 donble or sino-le nature of the frontal carina, hnt the species 

 of both g-ronps are closely related; the sjx'cies or snbspecies 

 aronnd Jclnine being still in a very indciiiiite condition. This 

 wonld indicate a nmch more recent iuniiiiii-ation. The species 

 of this group are all macropterons. Lcialolia IcIiikic and allied 

 species are attached to Metrosideros, a genus of tree that there 

 are reasons to believe, so Mr. J. F. Rock informs me, does not 

 belong to the most ancient portion of the Hawaiian flora. The 

 only species of this tribe known ontsi(h' of the Hawaiian Isl- 

 ands are one in Australia and one in South America, so we 

 must look to one or the other of these localities for the ances- 

 tors of the Hawaiian AloJilni. 



The above stated facts lead me to believe that the Hawaiian 

 AfoJiini are descended from two separate immigrants, the an- 

 cestor of the Alolta group having arrived at a very much 

 earlier date than the ancestor of the LeiaJoha group. Al- 

 tliough the latter is the more recent immigrant, yet it is not 

 a more highly specialized form, — rather the reverse, for the 

 short basal joint of the antenna is the more primitive in 

 ontogeny. 



Li^'Es OF Evolution, 



In dividing these species into genera Tvirkaldy followed 

 the general usage of considering the nature of the frontal 

 carinae as of primary importance. This brought Lei aloha 

 next to Aloha and Ncsorestias, and Ncsodryas next to Neso- 

 sydne and Dictyophoroddphax. The general build (^f these 

 insects does not admit of such an association, and the male 

 genitalia demonstrates the affinity of Leialoha and Nesodryas. 



Ontogeny indicates that the double frontal carina is the 

 more primitive form, as the nymphs of all the species have 

 two, the transition to a single carina, simplex or furcate, tak- 

 ing place at the last ecdysis. It thus becomes evident that the 

 character of a single frontal carina has arisen separately in 

 each group and has no ])hylogenetic significance. This line 



