REHN AND HEBAKD 35 



unarmed or with from one to five spines; cephalic tibiae armed 

 dorsad on the external margin with but three (rarely four) spines. 

 Caudal femora variable in length, proximal portion moderately 

 to decidedly bullate, ventro-internal margin unarmed or with 

 a number of spines; caudal tibiae with all margins well armed, 

 dorsal ones with greater number, distal spurs with dorsal pair 

 distinctly dorsal in position, median and ventral ones distinctly 

 ventral in insertion, median pair of average or unusual length; 

 caudal metatarsi with plantulae of short to great {calcaratus) 

 length. Supra-anal plate small, trigonal to rounded in both 

 sexes, seated in the emargination of the disto-dorsal abdominal 

 segment. Cerci of male styliform, of robust or elongate type 

 or corniform and elongate; tooth on internal face short and unci- 

 nate, elongate or corniform. Cerci of female simple and taper- 

 ing. Ovipositor of medium or considerable length, straight, 

 faintly or distinctly upcurved or very weakly decurved, apex 

 on median line or ventral in position. Subgenital plate of male 

 subtruncate to deeply fissate, styles varying from decided terete 

 structures to mere nodes; subgenital plate of female always 

 cleft, but this of variable degree and form, lateral portions of 

 the plate ranging from rounded to lanceolate produced. 



Classification. — The characters which stand out after detailed 

 study as of diagnostic value are: the general form of the disk 

 of the pronotum, the character of the caudal margin and the 

 lateral margins and angles of the same, the relative depth com- 

 pared with dorsal length of the lateral lobes of the same, the 

 degree of projection of the male tegmina, the general character 

 of the same, the form of the male cerci, the form of the subgenital 

 plate of the female, the relative length and proportionate prox- 

 imal inflation of the caudal femora and the character of the 

 caudal tibial distal (particularly internal) spurs. In addition the 

 degree of carination of the abdomen and the relative depth and 

 general form of the ovipositor are features usually of diagnostic 

 value, but not absolute for all the species, both showing varia- 

 tion in certain forms. 



One of the striking things demonstrated by our study of the 

 series of this genus is that the degree of development of the pro- 

 sternal spines has little or no significance, as we find them well 



TRANS. AM. ENT. SOC, XLII. 



