250 ENTOMOLOGICAL NEWS. [June, 'l6 



close relationship between the two ; but for that matter the 

 lines of descent of the Perlid, Phasmid, Grylloblattid, Forficu- 

 lid, Enibiid and Termitid groups all converge as we trace them 

 further back, so that it is extremely difficult to tell which are 

 the most closely related. The Grylloblattid group forms a dis- 

 tinct order termed the Not opt era (Ent. News, Vol. 26, p. 347), 

 which are among the most interesting and important of the 

 annectent forms surviving to the present day.* 



As shown in the accompanying diagram the Coleoptera are 

 rather closely related to the Forficulids, and also to the Em- 

 biids and Grylloblattids, but ultimately lead back to the Perlid 

 line of descent. Indeed, the Coleoptera are a much more an- 

 cient group than is usually thought to be the case, and although 

 some of the representatives of the group are quite highly 

 specialized, others show undoubted affinities with the lower 

 insects as shown in the diagram. The Apocolcoptera (Platyp- 

 sylloides) or Platypsyllidae form a distinct order, arising as 

 an offshoot from the main line of descent of the Coleoptera, 

 and in some respects they resemble the parasitic Forficuloid 

 group Hemimeridae. Whether this is due to a convergence in 

 form as the result of similar modes of life, or is due to the fact 

 that the Coleopteron and Forficuloid lines of descent closely 

 parallel each other, is not clear. 



The Forficulid line of descent parallels that of the Embiids 

 and Grylloblattids rather closely, as is shown by a comparison 

 of the rather primitive Forficulid Labiditrodcs, with specimens 

 of Grylloblatta and Embia major Imms. Furthermore, such 

 primitive Forficulids as Arixenia, show undoubted Perloid 

 affinities, and the Embiid, Forficulid, Grylloblattid and Perlid 

 lines of descent are to be considered as paralleling each other 

 extremely closely. Together with the other groups just men- 

 tioned, the Forficulids converge toward the Termitid and 

 Phasmid lines of development (the Phasmid Timcma having 

 retained certain characters suggestive of those found in the 



* The color of these insects is likewise extremely primitive, yellow 

 to brown-yellow being apparently the original color of the ancestral 

 Pterygota, while the paler shades (white or tinge of gray) are more 

 characteristic of the Apterygotan forms. 



