THE DECTICIN.E OF NORTH AMERICA— CA UDELL. 287 



except in Capnohotes and A/wplodusa, aborted or shorter than the 

 abdomen. 



The possession of a free plantula below the base of the posterior 

 tarsns is usually a conspicuous character (tig. 1 ^>.), but in some forms 

 it is not so obvious, though alwa3^s distinct. In many genera there is 

 visible between the cerci of the male, below or ])y the side of the 

 supraanal plate, two paired organs, usually more or less compressed. 

 These are called supragenital-or inf racercal-plates. rhey are generally' 

 obscure or wholly invisible, being hidden beneath the last abdominal 

 segment, but sometinies they are more prominent than the cerci, as 

 in Aiilaotliora.r and Nednha. 



The cerci of the male are usually of various shapes and usually 

 furnished with teeth, furnishing good synoptic characters, but in a 

 few genera they are simple, like those of the females. The last 

 abdominal segment of the males is often of various shapes. As used 

 here the last aV)dominal segment means the apical portion onW, not 

 the whole segment. 



We have twenty genera of Decticintv in North America. Most of 

 the described species have been characterized b}^ 

 Dr. Scudder, and the genera put in tabular form by 

 the same author." His classitication is based par- 

 tially upon the armature of the anterior tibia^ a 

 character which I tind most unreliable. This char- fiu. i.-s.de view„f a 



,.,,.,. . TT FOOT SHOWIN(; THE 



acter IS less used m the classihcations of Herman'' plantula (p) below 

 and Rrunner.'' thekirsttarsalseu- 



me\t. 



In the detiJiition of species I tind that the cerci of 

 the male furnish valuable characters. For the differentiation of the 

 genera I have constructed a table based on somewhat artificial charac- 

 ters. Many writers maintain that a table must represent the natural 

 sequence of the subjects treated and sacrifice the question of function 

 ability to that end. I believe, however, that the primary use of a table 

 is to enable one to correctly place the genera or species discussed, and 

 that the natural sequence should be otherwise indicated. The follow- 

 ing generic key is therefore recognitional rather than natural, but I 

 hope will serve the practical purpose intended, that of making easy 

 the identitication of the genera. 



KEY TO THE (iEXKKA OF NORTH AMERR'AN DECTUTN.K 



1. Wings short, rarely longer than the pronotnni and often, especially in the female, 



rudimentary or wanting 3 



Wings fully develope<l, extending far heyond the tip of the ahdomen in l)oth 

 sexes 2 



2. Presternum armed with a ]iair of spine.«; posterior femora armed helow on apical 



half with several distinct s] lines ('(ipnohotct<, p. olO 



Prosternum unarmed; posterior fcmoTa unarmed heluw inoploiJnftit, p. olS 



"(iuide Orth. X. A. (18<»7). ''Die Decticiden, 1.S74. 'Rev. Syst. Orth., 1893. 



