114 THE CANA.DIAN ENTOMOLOGIST 



ed in both groups, in the fore wing, and is unbranched in the hind wing. The 

 course of veins "Ri + a" and "M^" is astonishing similar in the hind wings of both 

 lypes of insects. 



While it has no direct bearing on the matter of indicating a close relation- 

 ship between the two groups, it may be mentioned that in the Psocids there is 

 a marked tendency toward the development of aberrations in the venation of cer- 

 tain individuals, and the venation of the wing of one side of the body may even 

 differ from that of its fellow on the other side of the body. Similarly in the 

 Zoraptera, there is also exhibited a marked tendency toward a variation in the 

 venation of certain individuals, and in a specimen of Zorotypus snyderi which I 

 have examined, the venation of the right fore wing was quite different from that 

 of the left fore wing, thus suggesting the operation of similar tendencies in the 

 nvo groups of msects. 



The evidence of the wing venation would add further support to the in- 

 dications of an extremely close relationship between Zoraptera and Psocids 

 furnished by other features of the body, and this relationship is so intimate that 

 it is quite evident that the Zoraptera should be placed in the superorder Panhom- 

 optera next to the Psocids. Furthermore, the Zoraptera are the nearest living 

 representatives of the types ancestral to the Psocids, and these in turn are very 

 like the ancestors of the Thysanoi)tera, Mallophaga, Anoi)leura. Hemiptera and 

 Homoptera. 



The orders of winged insects may be grouped into the following super- 

 Drders, according to the revised views expressed in an article recently published 

 in Psyche, Vol. 27, 1920, p. 125, which are further modified to a slight extent, 

 ir. ihe following list. 



Palaeodictyopteriod Superorder ( Panpalaeodictyoptera or Ephemeriformia) . . . . 

 Protephemeroida, Ephemeroida, Protodonata, Odonata, Palaeodictyoptera, 

 "Protohemiptera" etc. 



Plecopteroid Superorder ( Panplecoptera or Perliformia) 



Haplopteroida. Plecoptera, Hadentomoida, Embioida, Dermaptera, etc. 



Onhopteroid Superorder ( Panorthoptera or Phasmiformia) 



Protorthoptera, Grylloblattoida, I'hasmoida, Orthoptera, etc. 



Isopteroid Superorder ( Panisoptera or Blattiformia) 



Protoblattoida, Blattoida, Mantoida. Isoptera, etc. 



Psocoid Superorder ( Panhomoptera or Psociformia) 



Zoraptera. Psocoida. Mallophaga, Pediculoida, Thysanoptera, Homoptera, 

 Hemiptera, Palaeohemiptera, etc. 



Neuropteroid Superorder (Panneuroptera or Sialiformia) 



Neuroptera, Hymenoptera, Mecoptera, Protomecoptera, Paramecoptera, 

 Paratrichoptera. Trichoptera. Lepidoptera, Diptera, Siphonaptera, etc. The 

 Coleoptera and Strepsiptera may eventually be placed in this superorder, 

 but I have not been able to definitely decide concerning tnem or such forms 

 as the Megasecoptera. etc., which are also related to members of this super- 

 order. 



The Plecopteroid superorder appears to lead to the Neuropteroid super- 

 order, while the Isopteroid superorder appears to lead to the Psocoid superorder, 



