858 ZOOLOGY— INSECTS. 



ance with nature, if, while harmonizing the parts of a group with each other, 

 we tear asunder the links which hind it as a whole to other adjacent groups. 

 Moreover, I believe it is now generally conceded that, in ascending the 

 scale of being, we pass, as a general rule, from the generalized to the special- 

 ized, and find the lines we are tracing repeatedly branching and forming 

 other lines. 



Without attempting at present a further review of the author's general 

 arrangement, I will call attention to such changes in his work as relate to 

 our North American orthopteral fauna. 



Sphenarium, Ichthydion, and Pyrgomorpha are transferred to Pliymatidce. 



The last named genus as he has limited it, and in fact the characters 

 of this subfamily as he has given them, excludes our P. brevicornis, which, 

 as will hereafter be seen, has been retained in Truxalis.* 



His subfamily Acridiidce includes the following genera, which have 

 usually been placed in other divisions: — Xiphocera, Tropinotus, DictyopJiorus, 

 Rhomalea, Mcsojjs, and Opsomala. 



Our Rhomalea centurio (^mieroptera) is retained in the Dietyophorus of 

 Thunberg as D. reticulatus, the name given to it by that author in 1815. 

 This genus, as now limited, is distinguished by the following characters : — 

 The vertex and fastigium lying in the same plane and slightly declined, 

 and seen from the side forming a right angle with the frontal costa ; prono- 

 tum obtusely carinated; anterior margin forming an obtuse angle or rounded. 



Rhomalea is limited to the species possessing the following characters : — 

 The transverse impressions of the pronotum distinct ; anterior lobe destitute 

 of a carina; posterior lobe depressed, but ascending posteriorly; frontal 

 costa suddenly flattened below the ocellus. In this, he places B. miles, 

 Burm., but restores the specific name speciosa of Thunberg ; Acridium eolo- 

 ratum, Serv. (Chromacris colorata, Walk.), is also included. His specimen of 

 the latter species is from Mexico ; it is therefore probable that the locality 

 (Carolina) given by Serville for his specimen is a mistake. 



The author also introduces a new genus (Tceniopoda) into this rhoma- 

 lean group, which has the following as its distinguishing characters : — Fasti- 

 gium strongly deflexed, forming with the frontal costa as seen from the side 



* The reader will notice that, in speaking of Still's genera and subfamilies, I retain his method of 



spelling. 



