THE CANADIAN ENTOMOLOGIST 217 



The insects most closely related to the Embiids are the Plecop- 

 tera, which are probably the nearest living representatives of the 

 ancestral Pterygota, so that the Embiids were doubtless descended 

 from Plecoptera-like ancestors. From these " Plecopteroid " ances- 

 tors the Forficulid line of development branched off in one direc- 

 tion, while that of the Embiids branched off in the other direction, 

 and somewhere between the two (though doubtless nearer to the 

 Embiid than to the Forficulid line) arose the Grylloblattid and 

 Phasmid line of de\'elopment. Somewhere between these in turn 

 arose the Phasmodid, Tettigonid and Gryllid lijies of development, 

 while the Phylliids branched oiif from the Phasmid line of develop- 

 ment. From this, it may be seen that the Blattids are not near 

 the direct line of descent of the Grylloblattids, Phasmids, etc. ; 

 but this point will be more fully discussed elsewhere. 



Bibliography. 



1915. Brues & Melander. Key to the Families of North American 

 Insects; Boston, 1915. 



1915. Crampton. The Thoracic Sclerites and the Systematic 

 Position of Grylloblatta campodeiformis, etc.; Ent. News, 

 26, p. 337. 



1916. Crampton. The Lines of Descent of the Lower Pterygotan 

 Insects, etc.; Ent. News, 27, p. 244. 



1914. Walker. A New Species of Orthoptera, Forming a New 

 Genus and Family; Canadian Entomologist, 46, p. 93. 



Dr. Walker will shortly publish an article dealing with both 

 sexes of Grylloblatta. 



Abbreviations. 



Af. Antennifer, or process bearing the antenna. 

 At. Antennale, or ring at base of antenna. 



I. First antennal segment, or scape. 



II. Second antennal segment, or pedicel. 



III. Third antennal segment, or postpedicel. 



IV. Fourth segment of antenna, etc. 



