Vol. XXvi] ENTOMOLOGICAL NEWS 343 



cestors very like those of the Isoptera and Dermaptera (with 

 the Plecoptera), and although Grylloblatta is much nearer to 

 the Dermaptera than to the Isoptera, it furnishes a "connect- 

 ing link" between the two. As will be later discussed, Gryl- 

 loblatta also leads us to the common origin of the crickets and 

 katydids. 



The Coleoptera also combine certain features found in the 

 Dermaptera and Isoptera, but doubtless are descended from 

 ancestors nearer to the Dermaptera than to the Isoptera. The 

 fact that some beetle larvae have forceps-like terminal ab- 

 dominal appendages (e. g. Cucujus, Pyrochroa, etc.), while 

 others, such as the Carabidae, have segmented cerci, was for a 

 long time a very puzzling feature in attempting to determine the 

 ancestry of the Coleoptera ; but in the light of what has gone be- 

 fore (namely that the forceps of the Dermaptera are merely 

 modifications of the segmented cerci of the ancestral forms) the 

 occurrence of both forceps and segmented cerci in beetle lar- 

 vae becomes immediately comprehensible, and takes its logical 

 position in the general developmental scheme. 



Very closely related to the Isoptera, are the Zoraptera re- 

 cently described by Silvestri, 1913 ("Descrizione di un nuovo 

 ordine di insetti," Portici, 1913). I have not been able to 

 obtain any of these insects for examination, but it is quite 

 evident that they are very closely related to the Isoptera, and 

 also show certain Coleopterous affinities. Whether they are 

 annectent between the Isoptera and any other group, can only 

 be determined by a closer examination of the thoracic sclerites, 

 etc., which are not clearly shown in Silvestri's figures ; but I 

 would not be at all surprised if they should prove to possess 

 characters similar to the Grylloblattidae (and Dermaptera) 

 also. 



The Isoptera, as has been previously mentioned, are related 

 to the Grylloblattidae and Dermaptera. They are also closely 

 related to the Blattidae, perhaps more closely than to the Gryl- 

 loblattidae, and thus occupy a position between the two. The 

 Blattidae, on the other hand, are very closely related to the 

 Mantidae. The complicated interrelations of these various 



