854 ZOOLOGY INSECTS. 



lar ridire, which forms a sort of muffler, into which the mouth is drawn when 



o / ' 



at rest. 



Mouth covered by the advanced portion of the prosternum. 



Elytra and wings, when present, generally placed upon the sides of the 

 body, the latter exceeding the former in length ; these organs being appa- 

 rently pushed upon the sides by the extended pronotal shield. 



These differences in the external structure, which all must admit are 

 important, are accompanied by certain modifications of the internal struc- 

 ture, and certainly indicate important variations in habits 



Now, if we compare the species of Stal's subfamily Acridiidce with those 

 of his CEdipodida, or any other true Acridians, we shall find the tarsi in each 

 case furnished with a pad between the claws ; the shortened, shield-like pro- 

 notum ; the prosternum drawn up ; the mouth free ; the elytra, when pres- 

 ent, always equal to or exceeding the wings in length, and generally meet- 

 ing or overlapping each other above the abdomen. 



It is therefore clear that the true Acridians and the Tettigi are more 

 Avidely separated from each other than the groups of the former ; and a true 

 arrangement ought to indicate this difference. For these reasons, I still hold 

 that the Tettigi should be separated as a subfamily, and that the other 

 groups of the true Acridians should be considered as subordinate divisions. 



It will be observed that I have admitted that my arrangement should 

 probably be somewhat modified ; also, that, in speaking of certain groups, I 

 have used the expression " True Acridians ". My reason for this is that a 

 more thorough examination of exotic forms has convinced me that the Pro- 

 scop ite constitute a distinct subfamily, equivalent to the Tettigi. Whether the 

 Mastacidce should be embraced in the same division as Stal in effect does 

 in his Conspectus of his subfamilies, I am unable to say ; but I have consid- 

 erable doubt as to the propriety of this course. 



A single glance at a typical species of Proscopia is sufficient to reveal 

 even to a superficial observer important variations from the true Acridian 

 type*. Their elongate, cylindrical bodies, long, slender legs, and general 

 appearance would lead us, at the first glance, as it did Stoll, to place them 

 among the apterous Phasmce In fact, Ccphalocoema subaptera, West (Arcan. 

 Ent, ii, 55, pi. 63, fig. 2), might easily be taken by the iinscientific 



