HANCOCK 85 



forms an inviting field is o])en for the study of more definite 

 quantitative variation. Summing up the tendency of evolu- 

 tion from the material on hand, it appears that when we pass 

 from the south to the north, the long, extenuate form given 

 to the body is gradually through adaptive changes given way 

 to slightly more robustness of stature and abbreviation. 

 Examples remain of both types in the north, but the ancestral 

 forms with long wings seem numerically to be much less 

 represented and to tend to extinction. 



TETTIX ARENOSUS, BURM. 



Plate IV., Figs. s-gb. 

 Plate III., Fig. 3. 



Body moderatel)' slender, rugose-granulate. Verte.x viewed 

 from above about twice the width of one of the eyes, depressed 

 anteriorly, advanced scarcely beyond the anterior margin of 

 the eyes, the front margin subtruncate or scarcely convex, 

 rounding laterally into the sides, lateral margins subparallel, 

 on either side of the median carina longitudinally fossulate, 

 scarcely deeper between the middle of the eyes; median carina 

 of vertex indistinct, barely projecting as a minute tooth at the 

 middle of the front border, occiput behind the eyes naked, 

 crown of head in profile not quite so elevated as the eyes. 

 Frontal costa in profile advanced beyond the eyes equal to 

 about one-sixth the diameter of one of them, lightly sinuate 

 between the lower portion of the eyes, very little protuberant 

 between the antennje, at the junction with the median carina 

 of the vertex projecting as a small, angulate prominence before 

 the eyes with apex a little rounded, viewed in front the frontal 

 costa narrowly furcate, the rami parallel, very closely approxi- 

 mate. Eyes moderately large, in dorsal view especially promi- 

 nent. Antennae appreciably slender, articles strongly elongate. 

 Pronotum anteriorly strictly truncate, in front of the shoulders 

 rather strongly constricted, posteriorly long extenuate acute, 

 process strongly passing the posterior femora, but not extended 

 so far as the wings; dorsum between the shoulders trans- 

 versely flattened, scarcely convex, rather narrow, between the 



