344 ENTOMOLOGICAL NEWS [Oct., '15 



forms makes it impossible to arrange the orders in a dichotom- 

 ously branching phylogenetic tree, since such an arrangement 

 does not show the fact that several of the groups may overlap 

 or approach one another from different directions, but merely 

 allows for the branching in one plane. 



As was previously mentioned, the Grylloblattidae occupy 

 an intermediate position between the Dermaptera and Isop- 

 tera, and apparently branched off at an early stage from the 

 ancestral Dermaptera-Plecopteron group. The tendency to- 

 ward the development of an ovipositor (present in other primi- 

 tive insects) has apparently found opportunity for expression 

 in the Grylloblattidae, and in the crickets and katydids, which 

 are descended from ancestors not unlike the Grylloblattidae. 

 Indeed, the terminal abdominal structures of such crickets as 

 Oethancus are strikingly similar to those of Grylloblatta, and 

 the fore-runners of many structures which reach their greater 

 development in the crickets and katydids are clearly evidenced 

 in the Grylloblattidae. The crickets and katydids approach 

 one another in such forms as Gryllacris, and have apparently 

 descended from a common stock. This common stock, in turn, 

 was derived from forms not unlike the Grylloblattidae — in 

 other words, the Grylloblattidae have not greatly changed from 

 the ancestral forms, although they, of course, have developed 

 modifications of their own, as is true of all forms now living. 



I have not seen such forms as Phasmodes, Zaprochilns, etc., 

 but judging from the figures by Caudell, 1912 ("Orthoptera," 

 family "Locustidae ;" Genera Insect orum, fascicle 138), Phas- 

 modes is an insect allied to the katydids, and related to both 

 Phasmidae and Grylloblattidae. The Phasmidae, on the other 

 hand are related to the Phylliidae {Phyllium-Wko. insects), and 

 the latter (Phylliidae) are in reality nothing but greatly flat- 

 tened, walking grasshoppers ! 



The line of descent of the grasshoppers ("Acridiidae") is, I 

 think, slightly different from that of the crickets (Gryllidae) 

 and katydids ("Locustidae"), although it closely parallels the 

 latter line. Judging from the antennae, mouthparts, thoracic 

 sclerites, the nature of the "ovipositor," etc., the grasshoppers 

 are in some respects more closely related to the Phylliidae than 



