201 



The Aloliae consists of several groups of very distinct in- 

 sects ; even the gen us Nesosydne contains groups of diverse 

 species. This wouhl indicate a very ancient immigration. 

 Another point of interest is that a majority of these species 

 are brachypterous. 



TheLeialohae consists of two genera, sejiarated by the 

 double or single nature of the frontal carina, but the species 

 of both groups are closely related ; the species or subspecies 

 around lehuae being still in a very indefinite condition. This 

 would indicate a much more recent inunigration. The species 

 of this group are all macropterous. Leialulia lehuae 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 outside 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 AJoliini. 



The above stated facts lead me to believe that the Hawaiian 

 Aloliini are descended fi'om t^vo separate immigrants, the an- 

 cestor of the Alolia group having arrived at a very much 

 earlier (bite than the ancestor of the Leialoha group. Al- 

 though 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. 



LixEs OF Evolution. 



In dividing these species into genera Kirkaldy followed 

 the general usage of considering the nature of the frontal 

 carinae as of primary importance. This brought Leialoha 

 next to Aloha and Nesorestias, and Nesodryas next to Neso- 

 sydne and Dictyophorodclphax. The general build of these 

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

 genitalia demonstrates the affinity of Leialoha and Nef<odnjas. 



Ontogeny indicates that the double frontal carina is the 

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

 tw^o, 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 grou}) and has no phylogenetic significance. This line 



