20 Illinois State Laboratory of Natural History. 



Genus 3. Tettigonia Geoffk. 



Tettigonia Geoffr., Hist, des Ins. I., p. 429. 



Body elongate, slender. Head rounded or triangular in 

 front, not wider than the thorax, above generally flat, vertex 

 not reaching the front margin. Front large, convex, striate as 

 usual, the portion reflexed over the front edge only slightly, 

 and sometimes not at all, striate. (Uypeus large, generally 

 convex. Ocelli nearer the eyes than to each other. Gena? 

 large, deflexed, tips projecting donwards, and not forwards and 

 outwards as in the preceding genera. Pronotum hexagonal, 

 with the scutellar angles often very obtuse and the outer side 

 much rounded, deflexed at the sides. Scutellum triangular, 

 divided by the usual transverse groove; surface c^uite smooth. 

 Beneath, the coxtt are very large and the raesothoracic epi- 

 sternum is large and flat. Legs with the tibite long, prismatic, 

 and spinulose. Elytra with four different types of venation, 

 with a small marginal membrane. Wings with the second 

 sector having the two branches connected with the first and 

 third simple sectors by short cross-veins. Fourth sector forked 

 and fifth simple. Marginal vein apparently attaining the mar- 

 gin immediately after joining the posterior fork of the fourth 

 sector. 



This genus is one of large extent, possessing members both 

 common and variable. Indeed it may be considered one of the 

 dominant groups of insects. Many of our species belong to 

 the genus Diedrocephala, but the characters which separate it 

 from Tettigonia are not of generic importance, as European 

 authors now agree. Nevertheless differences enough do exist 

 to divide it into a number of well-marked subgenera and 

 sections. 



One of the most striking of these is represented by a sin- 

 gle species, T.tr}pi(nct((t(( Fitch. The peculiarity of this species 

 consists in the short vertex, the renuxrkably long front and 

 clypeus, the absence of the anteapical cells in the elytra, and 

 also in the forking of the firsfc sector near the base, so that it 

 ap))ears like an additional sector. 



Tlie second section is represented by T. bifida of Say, and 

 is characterized by its very short, rounded vertex, the absence 



