11(3 Psyche [June 



ON" SOME BECENT EEMARKS ON l^HE PHYLOGENY OP 



HOMOPTERiA. 



By F. Muie, 



Hawaiian Sugar Planters' Experiment Station, 



Honolulu, T. H. 



In a recent publication Dr. G. C. Crampton^ remarks: "In any 

 phylogenetic study we must consider the lowest representatives 

 rather than the highly specialized memliers of a group." 



Unfortunately Dr. Crampton, on more than one occasion when 

 discussing the phylogeny of Homoptera, has not followed this 

 good advice. In a recent paper- he has compared the wing of a 

 Psyllid and a wing of a Psocid and concluded that their simi- 

 larity is due to their common ancestry. The -Psocid wing he fig- 

 ures is a specialized one and not the lowest representative of the 

 group, and Psyllida? are highly specialized Homoptera. Any simi- 

 larity between the venation of the wings of these two insects ih 

 therefore of no phylogenetic significance, but due to convergence. 



As I am not an authority upon the Psocidffi I can only support 

 my contention by a comparison of the Psocid wing figured by 

 Dr. Crampton with such genera as Amphientomum and Cyma- 

 topsocus, where the venation is more generalized but still too 

 specialized to be ancestral to the Homoptera. 



My contention that the Psyllidse do not represent the primitive 

 type of Homoptera is based upon a detailed study of the sui)- 

 order. The evidence is too lengthy to give in detail in this paper, 

 but the following is a brief summary of some of the points. 



The Heraiptera form a homogeneous and monophyletic order 

 characterized by a unique sha]ie and arrangement of the mouth 

 parts found in no other order of insects. Although the order i& 

 of great size and the forms found within it are very diverse, yet 

 the mouthparts are always of tlie same type and far more uniform 

 than is found in any other of the large orders. That such a typo 

 of mouth organs should have arisen independently in two or more 

 groups seem.s higlily improbable. 



The nearest ap]n-oach to the Hemi])terous mouthparts is found 



» Proo. Ent. Soc. Washington 23, 2. p. 37 (1921). 

 ^Ent. News XXII, No. 4, p. 97-105 (1921). 



