1909.] 



NATURAL SCIENCES OF PHILADELPHIA. 



125 



grooved on the internal face, much shorter than veliei, much more acute 

 and less subequal than in persimilis. 



Subgenital opercule. Nearest to veliei, but blunter. 



A key to the females of the five species before us would be as follows : 



A.— Cerci hardly more than half the length of the eighth abdominal 

 segment. 

 B. — Subgenital opercule arcuate at the apex, . femorata. 



BB. —Subgenital opercule arcuato-truncate at the apex with a 

 distinct median projecting finger, . . arizonensis. 



A A. — Cerci decidedly more than half the length of the eighth abdominal 

 segment. 

 B. — Apical margin of the subgenital opercule not reaching to the 

 apical margin of the eighth dorsal abdominal segment. 

 C. — Head narrow, but little exceeding the cephalic width 

 of the mesonotum. Cerci as long as the ninth dorsal 



abdominal segment, . veliei. 



CC. — Head broad, half again as wide as the cephalic width 

 of the mesonotum. Cerci no more than half the 

 length of the ninth dorsal abdominal segment, 



mesillana. 



BB. — Apical margin of the subgenital opercule reaching to the 



apical margin of the eighth dorsal abdominal segment, 



persimilis. 



Three of the specimens of mesillana measure as follows : 



Of the series referred to mesillana, a single one (adult) was taken at 

 El Paso on July 17 on mesquite in the desert, an immature individual 

 was collected at the same place on July 10 on the irrigated land along 



