Vol. XXVli] ENTOMOLOGICAL NEWS. 305 



the basis of the closeness of their lines of descent. These are 

 as follows: i. The section Palaeopteradclphia, or Palaeop- 

 teron (Blattid) brotherhood, comprising the Blattids (and 

 possibly the Mantids also.) 2. The section Plecoptera- 

 dclphia, or Plecopteron brotherhood, comprising the Ple- 

 coptera and those insects whose lines of descent parallel 

 that of the Plecoptera (e. g., the Embiids, Forficulids, Gryllo- 

 blattids, Coleoptera, Termites, Gryllids, Tettigonids, Locustids, 

 Phasmids, Phylliids, etc.). 3. The section NcuropteradelpJiia, 

 or Neuropteron brotherhood, comprising all of those forms 

 descended from ancestors similar to those of the Neuroptera 

 (e. g., the Neuropteroid insects, Homopteroid forms, Hemip- 

 tera, Lepidoptera, Diptera, etc.). 4. The Zygopteradclphia, 

 or Zygopteron brotherhood, comprising a small aberrant group 

 (Anisoptera, Zygoptera, etc.), which may possibly be included 

 in one of the other sections. 5. The Plcctoptcradclphla, or 

 Plectopteron brotherhood, comprising the very primitive though 

 strongly aberrant Ephernerid group. These five sections rep- 

 icsent five evolutionary groups, although some of them might 

 possibly be included in certain of the other groups, thus re- 

 ducing the number ; but I think that each of the five is distinct 

 enough to merit being regarded as a separate line of evolution. 

 The section Plecopteradclphia (Plecopteron brotherhood) 

 and the section Ncuroptcradelphia (Neuropteron brotherhood) 

 comprise the greater part of all winged insects, and are thus 

 by far the most important of the evolutionary lines. Whether 

 the Plectoptcraddphla ( Kphemerid brotherhood) and Zyyop- 

 teradclphia are sufficiently distinct from each other and from 

 the Plecopteron group, to be considered as separate sections 

 is open to question; and the fact that the Palacoptcradclphhi 

 (Blattid brotherhood) is closely related to the Plecopteron 

 group also raises the question of its being sufficiently distinct 

 to be regarded as a separate section. It must be borne in 

 mind, however, that all of the sections are ultimately closely 

 related, and the Plecopteron group itself is closely related to 

 the Neuropteron group, but both appear to represent definite 

 foci about which numerous other forms cluster ; and the other 



