74 STUDIES IN AMERICAN TETTIGONIIDAE (oRTHOPTERA) 



are sublanceolate and more produced than in any of the other 

 forms of the genus. True dorsalis can be readily distinguished, 

 in addition, by the weak lateral carinae of the pronotal disk 

 and the more elongate and more slender caudal femora. 



Morphological Azotes.— This species exhibits the same amount 

 of variation in the relative proportion of the greatest (caudal) 

 width of pronotal disk to length of the same, as found in 

 davisi and the other species treated in the preceding pages. In 

 the male sex alone this ratio varies from 56 to 64 per cent and 

 in the two females from Lookout Mountain, Tennessee, the varia- 

 tion is so great that we get the decidedly different ratios of 54 

 and 67 per cent. The remarks we have already made regarding 

 the non-correlation of this ratio difference with the width of the 

 area of greatest convergence of the lateral carinae of the disk, 

 i. e. at cephahc third to fourth, is strikingly illustrated and sup- 

 ported by these two Lookout Mountain specimens, as while they 

 are so strikingly different in their other ratios they have exactly 

 the same least width of the disk. The cephahc margin of the 

 disk of the pronotum varies from subtruncate to distinctly arcu- 

 ato-emarginate, and this in the large Dias Creek series alone. 

 The caudal margin of the pronotal disk is always well arcuate and 

 though the degree of the same varies that portion is never sub- 

 truncate. The lateral lobes of the pronotum have Httle variation 

 in the form of the humeral sinus, which is broad and relatively 

 well indicated. The disto-clorsal abdominal segment in both 

 sexes is always angularly emarginate mesad, the exact angle 

 varying somewhafand the deeper portion of the angle is more or 

 less rotundate. The supra-anal plate of the male is always tri- 

 gonal and sulcate. The cerci of the male show a considerable 

 amount of individual variation in material from the same locality 

 and also some geographic chfference, this being due to an attenua- 

 tion or a shortening and thickening of the cercus, the tooth hold- 

 ing relatively the same position in all. In the more robust type 

 of cercus, the proximal portion is slightly disproportionately thick- 

 ened. The tooth varies little in character, but is more decided 

 and heavier in southern specimens. The male subgenital plate is 

 always fissate, the apparent degree depending on the amount to 

 which the plate has been compressed in drying, and the styles vary 



